libbpf: Add libbpf_version() function to get library version at runtime #371
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As a response to patches adding libbpf support to iproute2, an extensive discussion ensued about libbpf version visibility and enforcement in tools using the library[0]. In particular, two problems came to light: 1. If a tool is statically linked against libbpf, there is no way for a user to discover which version of libbpf the tool is using, unless the tool takes particular care to embed the library version at build time and print it. 2. If a tool is dynamically linked against libbpf, but doesn't use any symbols from the latest library version, the library version used at runtime can be older than the one used at compile time, and the application has no way to verify the version at runtime. To make progress on resolving this, let's add a libbpf_version() function that will simply return a version string which is embedded into the library at compile time. This makes it possible for applications to unambiguously get the library version at runtime, resolving (2.) above, and as an added bonus makes it easy for applications to print the library version, which should help with (1.). [0] https://lore.kernel.org/bpf/20201109070802.3638167-1-haliu@redhat.com/T/#t Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
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Master branch: ea87ae8 |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=386971 irrelevant now. Closing PR. |
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
May 4, 2023
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
yurinnick
pushed a commit
to yurinnick/kernel-patches-bpf
that referenced
this pull request
May 4, 2023
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty kernel-patches#371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
May 5, 2023
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
yurinnick
pushed a commit
to yurinnick/kernel-patches-bpf
that referenced
this pull request
May 5, 2023
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty kernel-patches#371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Jun 2, 2023
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Jun 5, 2023
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 7, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 7, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 7, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 8, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 9, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 9, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 9, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 10, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 10, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 10, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 10, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 10, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 10, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Oct 12, 2025
The test does the following for IPv4/IPv6 x TCP/UDP sockets
with/without sk->sk_bypass_prot_mem, which can be turned on by
net.core.bypass_prot_mem or bpf_setsockopt(SK_BPF_BYPASS_PROT_MEM).
1. Create socket pairs
2. Send NR_PAGES (32) of data (TCP consumes around 35 pages,
and UDP consuems 66 pages due to skb overhead)
3. Read memory_allocated from sk->sk_prot->memory_allocated and
sk->sk_prot->memory_per_cpu_fw_alloc
4. Check if unread data is charged to memory_allocated
If sk->sk_bypass_prot_mem is set, memory_allocated should not be
changed, but we allow a small error (up to 10 pages) in case
other processes on the host use some amounts of TCP/UDP memory.
The amount of allocated pages are buffered to per-cpu variable
{tcp,udp}_memory_per_cpu_fw_alloc up to +/- net.core.mem_pcpu_rsv
before reported to {tcp,udp}_memory_allocated.
At 3., memory_allocated is calculated from the 2 variables at
fentry of socket create function.
We drain the receive queue only for UDP before close() because UDP
recv queue is destroyed after RCU grace period. When I printed
memory_allocated, UDP bypass cases sometimes saw the no-bypass
case's leftover, but it's still in the small error range (<10 pages).
bpf_trace_printk: memory_allocated: 0 <-- TCP no-bypass
bpf_trace_printk: memory_allocated: 35
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ sysctl
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- TCP w/ bpf
bpf_trace_printk: memory_allocated: 0
bpf_trace_printk: memory_allocated: 0 <-- UDP no-bypass
bpf_trace_printk: memory_allocated: 66
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ sysctl (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
bpf_trace_printk: memory_allocated: 2 <-- UDP w/ bpf (2 pages leftover)
bpf_trace_printk: memory_allocated: 2
We prefer finishing tests faster than oversleeping for call_rcu()
+ sk_destruct().
The test completes within 2s on QEMU (64 CPUs) w/ KVM.
# time ./test_progs -t sk_bypass
#371/1 sk_bypass_prot_mem/TCP :OK
#371/2 sk_bypass_prot_mem/UDP :OK
#371/3 sk_bypass_prot_mem/TCPv6:OK
#371/4 sk_bypass_prot_mem/UDPv6:OK
#371 sk_bypass_prot_mem:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
real 0m1.481s
user 0m0.181s
sys 0m0.441s
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
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Pull request for series with
subject: libbpf: Add libbpf_version() function to get library version at runtime
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=386971