Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

ldoption broken for lld (lld's fault: -v can mask unknown -z value errors) #217

Closed
nickdesaulniers opened this issue Oct 15, 2018 · 1 comment
Closed

ldoption broken for lld (lld's fault: -v can mask unknown -z value errors) #217

nickdesaulniers opened this issue Oct 15, 2018 · 1 comment
Labels
[BUG] llvm A bug that should be fixed in upstream LLVM [FIXED][LLVM] 8 This bug was fixed in LLVM 8.0 [TOOL] lld The issue is relevant to LLD linker

Comments

@nickdesaulniers
Copy link
Member

nickdesaulniers commented Oct 15, 2018 •
edited by nathanchance
Loading

https://llvm.org/pr39289

forked from #31
@nickdesaulniers nickdesaulniers added [BUG] llvm A bug that should be fixed in upstream LLVM [TOOL] lld The issue is relevant to LLD linker labels Oct 15, 2018
@nickdesaulniers
Copy link
Member Author

Fixed https://reviews.llvm.org/rL344514

@tpimh tpimh added the [FIXED][LLVM] 8 This bug was fixed in LLVM 8.0 label Oct 17, 2018
nathanchance pushed a commit that referenced this issue Jan 22, 2021
@josefbacik @kdave
btrfs: fix lockdep splat in btrfs_recover_relocation
fb28610 
While testing the error paths of relocation I hit the following lockdep
splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.10.0-rc6+ #217 Not tainted
  ------------------------------------------------------
  mount/779 is trying to acquire lock:
  ffffa0e676945418 (&fs_info->balance_mutex){+.+.}-{3:3}, at: btrfs_recover_balance+0x2f0/0x340

  but task is already holding lock:
  ffffa0e60ee31da8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x100

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (btrfs-root-00){++++}-{3:3}:
	 down_read_nested+0x43/0x130
	 __btrfs_tree_read_lock+0x27/0x100
	 btrfs_read_lock_root_node+0x31/0x40
	 btrfs_search_slot+0x462/0x8f0
	 btrfs_update_root+0x55/0x2b0
	 btrfs_drop_snapshot+0x398/0x750
	 clean_dirty_subvols+0xdf/0x120
	 btrfs_recover_relocation+0x534/0x5a0
	 btrfs_start_pre_rw_mount+0xcb/0x170
	 open_ctree+0x151f/0x1726
	 btrfs_mount_root.cold+0x12/0xea
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 vfs_kern_mount.part.0+0x71/0xb0
	 btrfs_mount+0x10d/0x380
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 path_mount+0x433/0xc10
	 __x64_sys_mount+0xe3/0x120
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (sb_internal#2){.+.+}-{0:0}:
	 start_transaction+0x444/0x700
	 insert_balance_item.isra.0+0x37/0x320
	 btrfs_balance+0x354/0xf40
	 btrfs_ioctl_balance+0x2cf/0x380
	 __x64_sys_ioctl+0x83/0xb0
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&fs_info->balance_mutex){+.+.}-{3:3}:
	 __lock_acquire+0x1120/0x1e10
	 lock_acquire+0x116/0x370
	 __mutex_lock+0x7e/0x7b0
	 btrfs_recover_balance+0x2f0/0x340
	 open_ctree+0x1095/0x1726
	 btrfs_mount_root.cold+0x12/0xea
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 vfs_kern_mount.part.0+0x71/0xb0
	 btrfs_mount+0x10d/0x380
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 path_mount+0x433/0xc10
	 __x64_sys_mount+0xe3/0x120
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &fs_info->balance_mutex --> sb_internal#2 --> btrfs-root-00

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-root-00);
				 lock(sb_internal#2);
				 lock(btrfs-root-00);
    lock(&fs_info->balance_mutex);

   *** DEADLOCK ***

  2 locks held by mount/779:
   #0: ffffa0e60dc040e0 (&type->s_umount_key#47/1){+.+.}-{3:3}, at: alloc_super+0xb5/0x380
   #1: ffffa0e60ee31da8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x100

  stack backtrace:
  CPU: 0 PID: 779 Comm: mount Not tainted 5.10.0-rc6+ #217
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x8b/0xb0
   check_noncircular+0xcf/0xf0
   ? trace_call_bpf+0x139/0x260
   __lock_acquire+0x1120/0x1e10
   lock_acquire+0x116/0x370
   ? btrfs_recover_balance+0x2f0/0x340
   __mutex_lock+0x7e/0x7b0
   ? btrfs_recover_balance+0x2f0/0x340
   ? btrfs_recover_balance+0x2f0/0x340
   ? rcu_read_lock_sched_held+0x3f/0x80
   ? kmem_cache_alloc_trace+0x2c4/0x2f0
   ? btrfs_get_64+0x5e/0x100
   btrfs_recover_balance+0x2f0/0x340
   open_ctree+0x1095/0x1726
   btrfs_mount_root.cold+0x12/0xea
   ? rcu_read_lock_sched_held+0x3f/0x80
   legacy_get_tree+0x30/0x50
   vfs_get_tree+0x28/0xc0
   vfs_kern_mount.part.0+0x71/0xb0
   btrfs_mount+0x10d/0x380
   ? __kmalloc_track_caller+0x2f2/0x320
   legacy_get_tree+0x30/0x50
   vfs_get_tree+0x28/0xc0
   ? capable+0x3a/0x60
   path_mount+0x433/0xc10
   __x64_sys_mount+0xe3/0x120
   do_syscall_64+0x33/0x40
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This is straightforward to fix, simply release the path before we setup
the balance_ctl.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
[BUG] llvm A bug that should be fixed in upstream LLVM [FIXED][LLVM] 8 This bug was fixed in LLVM 8.0 [TOOL] lld The issue is relevant to LLD linker
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
2 participants
@tpimh @nickdesaulniers