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miss unsafe documentation #19

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Richardhongyu opened this issue Jan 8, 2024 · 0 comments
Open

miss unsafe documentation #19

Richardhongyu opened this issue Jan 8, 2024 · 0 comments
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good first issue Good for newcomers

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@Richardhongyu
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// rust/kernel/kernelh.rs
    arg1: *const c_char,
    arg2: *const c_char,
) -> *mut c_char {
    unsafe { bindings::kasprintf(gfp, fmt, arg1, arg2) }

There should be an unsafe comment above the unsafe block.
@Richardhongyu Richardhongyu added the good first issue Good for newcomers label Oct 6, 2024
shannmu pushed a commit to shannmu/RROS that referenced this issue Dec 15, 2024
@sassmann @anguy11
iavf: fix hang on reboot with ice
4e264be 
When a system with E810 with existing VFs gets rebooted the following
hang may be observed.

 Pid 1 is hung in iavf_remove(), part of a network driver:
 PID: 1        TASK: ffff965400e5a340  CPU: 24   COMMAND: "systemd-shutdow"
  #0 [ffffaad04005fa50] __schedule at ffffffff8b3239cb
  BUPT-OS#1 [ffffaad04005fae8] schedule at ffffffff8b323e2d
  BUPT-OS#2 [ffffaad04005fb00] schedule_hrtimeout_range_clock at ffffffff8b32cebc
  BUPT-OS#3 [ffffaad04005fb80] usleep_range_state at ffffffff8b32c930
  BUPT-OS#4 [ffffaad04005fbb0] iavf_remove at ffffffffc12b9b4c [iavf]
  BUPT-OS#5 [ffffaad04005fbf0] pci_device_remove at ffffffff8add7513
  BUPT-OS#6 [ffffaad04005fc10] device_release_driver_internal at ffffffff8af08baa
  BUPT-OS#7 [ffffaad04005fc40] pci_stop_bus_device at ffffffff8adcc5fc
  BUPT-OS#8 [ffffaad04005fc60] pci_stop_and_remove_bus_device at ffffffff8adcc81e
  BUPT-OS#9 [ffffaad04005fc70] pci_iov_remove_virtfn at ffffffff8adf9429
 BUPT-OS#10 [ffffaad04005fca8] sriov_disable at ffffffff8adf98e4
 BUPT-OS#11 [ffffaad04005fcc8] ice_free_vfs at ffffffffc04bb2c8 [ice]
 BUPT-OS#12 [ffffaad04005fd10] ice_remove at ffffffffc04778fe [ice]
 BUPT-OS#13 [ffffaad04005fd38] ice_shutdown at ffffffffc0477946 [ice]
 BUPT-OS#14 [ffffaad04005fd50] pci_device_shutdown at ffffffff8add58f1
 BUPT-OS#15 [ffffaad04005fd70] device_shutdown at ffffffff8af05386
 BUPT-OS#16 [ffffaad04005fd98] kernel_restart at ffffffff8a92a870
 BUPT-OS#17 [ffffaad04005fda8] __do_sys_reboot at ffffffff8a92abd6
 BUPT-OS#18 [ffffaad04005fee0] do_syscall_64 at ffffffff8b317159
 BUPT-OS#19 [ffffaad04005ff08] __context_tracking_enter at ffffffff8b31b6fc
 BUPT-OS#20 [ffffaad04005ff18] syscall_exit_to_user_mode at ffffffff8b31b50d
 BUPT-OS#21 [ffffaad04005ff28] do_syscall_64 at ffffffff8b317169
 BUPT-OS#22 [ffffaad04005ff50] entry_SYSCALL_64_after_hwframe at ffffffff8b40009b
     RIP: 00007f1baa5c13d7  RSP: 00007fffbcc55a98  RFLAGS: 00000202
     RAX: ffffffffffffffda  RBX: 0000000000000000  RCX: 00007f1baa5c13d7
     RDX: 0000000001234567  RSI: 0000000028121969  RDI: 00000000fee1dead
     RBP: 00007fffbcc55ca0   R8: 0000000000000000   R9: 00007fffbcc54e90
     R10: 00007fffbcc55050  R11: 0000000000000202  R12: 0000000000000005
     R13: 0000000000000000  R14: 00007fffbcc55af0  R15: 0000000000000000
     ORIG_RAX: 00000000000000a9  CS: 0033  SS: 002b

During reboot all drivers PM shutdown callbacks are invoked.
In iavf_shutdown() the adapter state is changed to __IAVF_REMOVE.
In ice_shutdown() the call chain above is executed, which at some point
calls iavf_remove(). However iavf_remove() expects the VF to be in one
of the states __IAVF_RUNNING, __IAVF_DOWN or __IAVF_INIT_FAILED. If
that's not the case it sleeps forever.
So if iavf_shutdown() gets invoked before iavf_remove() the system will
hang indefinitely because the adapter is already in state __IAVF_REMOVE.

Fix this by returning from iavf_remove() if the state is __IAVF_REMOVE,
as we already went through iavf_shutdown().

Fixes: 9745780 ("iavf: Add waiting so the port is initialized in remove")
Fixes: a841733 ("iavf: Fix race condition between iavf_shutdown and iavf_remove")
Reported-by: Marius Cornea <mcornea@redhat.com>
Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
shannmu pushed a commit to shannmu/RROS that referenced this issue Dec 15, 2024
@biger410 @martinkpetersen
scsi: megaraid_sas: Fix deadlock on firmware crashdump
0b0747d 
The following processes run into a deadlock. CPU 41 was waiting for CPU 29
to handle a CSD request while holding spinlock "crashdump_lock", but CPU 29
was hung by that spinlock with IRQs disabled.

  PID: 17360    TASK: ffff95c1090c5c40  CPU: 41  COMMAND: "mrdiagd"
  !# 0 [ffffb80edbf37b58] __read_once_size at ffffffff9b871a40 include/linux/compiler.h:185:0
  !# 1 [ffffb80edbf37b58] atomic_read at ffffffff9b871a40 arch/x86/include/asm/atomic.h:27:0
  !# 2 [ffffb80edbf37b58] dump_stack at ffffffff9b871a40 lib/dump_stack.c:54:0
   # 3 [ffffb80edbf37b78] csd_lock_wait_toolong at ffffffff9b131ad5 kernel/smp.c:364:0
   # 4 [ffffb80edbf37b78] __csd_lock_wait at ffffffff9b131ad5 kernel/smp.c:384:0
   # 5 [ffffb80edbf37bf8] csd_lock_wait at ffffffff9b13267a kernel/smp.c:394:0
   # 6 [ffffb80edbf37bf8] smp_call_function_many at ffffffff9b13267a kernel/smp.c:843:0
   # 7 [ffffb80edbf37c50] smp_call_function at ffffffff9b13279d kernel/smp.c:867:0
   # 8 [ffffb80edbf37c50] on_each_cpu at ffffffff9b13279d kernel/smp.c:976:0
   # 9 [ffffb80edbf37c78] flush_tlb_kernel_range at ffffffff9b085c4b arch/x86/mm/tlb.c:742:0
   BUPT-OS#10 [ffffb80edbf37cb8] __purge_vmap_area_lazy at ffffffff9b23a1e0 mm/vmalloc.c:701:0
   BUPT-OS#11 [ffffb80edbf37ce0] try_purge_vmap_area_lazy at ffffffff9b23a2cc mm/vmalloc.c:722:0
   BUPT-OS#12 [ffffb80edbf37ce0] free_vmap_area_noflush at ffffffff9b23a2cc mm/vmalloc.c:754:0
   BUPT-OS#13 [ffffb80edbf37cf8] free_unmap_vmap_area at ffffffff9b23bb3b mm/vmalloc.c:764:0
   BUPT-OS#14 [ffffb80edbf37cf8] remove_vm_area at ffffffff9b23bb3b mm/vmalloc.c:1509:0
   BUPT-OS#15 [ffffb80edbf37d18] __vunmap at ffffffff9b23bb8a mm/vmalloc.c:1537:0
   BUPT-OS#16 [ffffb80edbf37d40] vfree at ffffffff9b23bc85 mm/vmalloc.c:1612:0
   BUPT-OS#17 [ffffb80edbf37d58] megasas_free_host_crash_buffer [megaraid_sas] at ffffffffc020b7f2 drivers/scsi/megaraid/megaraid_sas_fusion.c:3932:0
   BUPT-OS#18 [ffffb80edbf37d80] fw_crash_state_store [megaraid_sas] at ffffffffc01f804d drivers/scsi/megaraid/megaraid_sas_base.c:3291:0
   BUPT-OS#19 [ffffb80edbf37dc0] dev_attr_store at ffffffff9b56dd7b drivers/base/core.c:758:0
   BUPT-OS#20 [ffffb80edbf37dd0] sysfs_kf_write at ffffffff9b326acf fs/sysfs/file.c:144:0
   BUPT-OS#21 [ffffb80edbf37de0] kernfs_fop_write at ffffffff9b325fd4 fs/kernfs/file.c:316:0
   BUPT-OS#22 [ffffb80edbf37e20] __vfs_write at ffffffff9b29418a fs/read_write.c:480:0
   BUPT-OS#23 [ffffb80edbf37ea8] vfs_write at ffffffff9b294462 fs/read_write.c:544:0
   BUPT-OS#24 [ffffb80edbf37ee8] SYSC_write at ffffffff9b2946ec fs/read_write.c:590:0
   BUPT-OS#25 [ffffb80edbf37ee8] SyS_write at ffffffff9b2946ec fs/read_write.c:582:0
   BUPT-OS#26 [ffffb80edbf37f30] do_syscall_64 at ffffffff9b003ca9 arch/x86/entry/common.c:298:0
   BUPT-OS#27 [ffffb80edbf37f58] entry_SYSCALL_64 at ffffffff9ba001b1 arch/x86/entry/entry_64.S:238:0

  PID: 17355    TASK: ffff95c1090c3d80  CPU: 29  COMMAND: "mrdiagd"
  !# 0 [ffffb80f2d3c7d30] __read_once_size at ffffffff9b0f2ab0 include/linux/compiler.h:185:0
  !# 1 [ffffb80f2d3c7d30] native_queued_spin_lock_slowpath at ffffffff9b0f2ab0 kernel/locking/qspinlock.c:368:0
   # 2 [ffffb80f2d3c7d58] pv_queued_spin_lock_slowpath at ffffffff9b0f244b arch/x86/include/asm/paravirt.h:674:0
   # 3 [ffffb80f2d3c7d58] queued_spin_lock_slowpath at ffffffff9b0f244b arch/x86/include/asm/qspinlock.h:53:0
   # 4 [ffffb80f2d3c7d68] queued_spin_lock at ffffffff9b8961a6 include/asm-generic/qspinlock.h:90:0
   # 5 [ffffb80f2d3c7d68] do_raw_spin_lock_flags at ffffffff9b8961a6 include/linux/spinlock.h:173:0
   # 6 [ffffb80f2d3c7d68] __raw_spin_lock_irqsave at ffffffff9b8961a6 include/linux/spinlock_api_smp.h:122:0
   # 7 [ffffb80f2d3c7d68] _raw_spin_lock_irqsave at ffffffff9b8961a6 kernel/locking/spinlock.c:160:0
   # 8 [ffffb80f2d3c7d88] fw_crash_buffer_store [megaraid_sas] at ffffffffc01f8129 drivers/scsi/megaraid/megaraid_sas_base.c:3205:0
   # 9 [ffffb80f2d3c7dc0] dev_attr_store at ffffffff9b56dd7b drivers/base/core.c:758:0
   BUPT-OS#10 [ffffb80f2d3c7dd0] sysfs_kf_write at ffffffff9b326acf fs/sysfs/file.c:144:0
   BUPT-OS#11 [ffffb80f2d3c7de0] kernfs_fop_write at ffffffff9b325fd4 fs/kernfs/file.c:316:0
   BUPT-OS#12 [ffffb80f2d3c7e20] __vfs_write at ffffffff9b29418a fs/read_write.c:480:0
   BUPT-OS#13 [ffffb80f2d3c7ea8] vfs_write at ffffffff9b294462 fs/read_write.c:544:0
   BUPT-OS#14 [ffffb80f2d3c7ee8] SYSC_write at ffffffff9b2946ec fs/read_write.c:590:0
   BUPT-OS#15 [ffffb80f2d3c7ee8] SyS_write at ffffffff9b2946ec fs/read_write.c:582:0
   BUPT-OS#16 [ffffb80f2d3c7f30] do_syscall_64 at ffffffff9b003ca9 arch/x86/entry/common.c:298:0
   BUPT-OS#17 [ffffb80f2d3c7f58] entry_SYSCALL_64 at ffffffff9ba001b1 arch/x86/entry/entry_64.S:238:0

The lock is used to synchronize different sysfs operations, it doesn't
protect any resource that will be touched by an interrupt. Consequently
it's not required to disable IRQs. Replace the spinlock with a mutex to fix
the deadlock.

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Link: https://lore.kernel.org/r/20230828221018.19471-1-junxiao.bi@oracle.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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