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Issues have moved to the issues repository #217

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mpe opened this issue Jan 7, 2019 · 0 comments
Open

Issues have moved to the issues repository #217

mpe opened this issue Jan 7, 2019 · 0 comments

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@mpe
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mpe commented Jan 7, 2019

Issues have moved to the issues repository.
@mpe mpe pinned this issue Jan 7, 2019
mpe pushed a commit that referenced this issue Jan 24, 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: [email protected] # 4.4+
Reviewed-by: Qu Wenruo <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
mpe pushed a commit that referenced this issue Nov 27, 2022
@mhiramat
tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in …
e0d7526 
…kprobe_event_gen_test_exit()

When trace_get_event_file() failed, gen_kretprobe_test will be assigned
as the error code. If module kprobe_event_gen_test is removed now, the
null pointer dereference will happen in kprobe_event_gen_test_exit().
Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL
before dereference them.

BUG: kernel NULL pointer dereference, address: 0000000000000012
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 3 PID: 2210 Comm: modprobe Not tainted
6.1.0-rc1-00171-g2159299a3b74-dirty #217
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test]
Code: Unable to access opcode bytes at 0xffffffff9ffffff2.
RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246
RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000
RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c
RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800
R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f56b75be540(0000) GS:ffff88813bc00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __x64_sys_delete_module+0x206/0x380
 ? lockdep_hardirqs_on_prepare+0xd8/0x190
 ? syscall_enter_from_user_mode+0x1c/0x50
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Link: https://lore.kernel.org/all/[email protected]/

Fixes: 6483624 ("tracing: Add kprobe event command generation test module")
Signed-off-by: Shang XiaoJing <[email protected]>
Acked-by: Masami Hiramatsu (Google) <[email protected]>
Cc: [email protected]
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
mpe pushed a commit that referenced this issue Nov 27, 2022
@chenhuacai
LoongArch: Clear FPU/SIMD thread info flags for kernel thread
e428e96 
If a kernel thread is created by a user thread, it may carry FPU/SIMD
thread info flags (TIF_USEDFPU, TIF_USEDSIMD, etc.). Then it will be
considered as a fpu owner and kernel try to save its FPU/SIMD context
and cause such errors:

[   41.518931] do_fpu invoked from kernel context![#1]:
[   41.523933] CPU: 1 PID: 395 Comm: iou-wrk-394 Not tainted 6.1.0-rc5+ #217
[   41.530757] Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.pre-beta8 08/18/2022
[   41.544064] $ 0   : 0000000000000000 90000000011e9468 9000000106c7c000 9000000106c7fcf0
[   41.552101] $ 4   : 9000000106305d40 9000000106689800 9000000106c7fd08 0000000003995818
[   41.560138] $ 8   : 0000000000000001 90000000009a72e4 0000000000000020 fffffffffffffffc
[   41.568174] $12   : 0000000000000000 0000000000000000 0000000000000020 00000009aab7e130
[   41.576211] $16   : 00000000000001ff 0000000000000407 0000000000000001 0000000000000000
[   41.584247] $20   : 0000000000000000 0000000000000001 9000000106c7fd70 90000001002f0400
[   41.592284] $24   : 0000000000000000 900000000178f740 90000000011e9834 90000001063057c0
[   41.600320] $28   : 0000000000000000 0000000000000001 9000000006826b40 9000000106305140
[   41.608356] era   : 9000000000228848 _save_fp+0x0/0xd8
[   41.613542] ra    : 90000000011e9468 __schedule+0x568/0x8d0
[   41.619160] CSR crmd: 000000b0
[   41.619163] CSR prmd: 00000000
[   41.622359] CSR euen: 00000000
[   41.625558] CSR ecfg: 00071c1c
[   41.628756] CSR estat: 000f0000
[   41.635239] ExcCode : f (SubCode 0)
[   41.638783] PrId  : 0014c010 (Loongson-64bit)
[   41.643191] Modules linked in: acpi_ipmi vfat fat ipmi_si ipmi_devintf cfg80211 ipmi_msghandler rfkill fuse efivarfs
[   41.653734] Process iou-wrk-394 (pid: 395, threadinfo=0000000004ebe913, task=00000000636fa1be)
[   41.662375] Stack : 00000000ffff0875 9000000006800ec0 9000000006800ec0 90000000002d57e0
[   41.670412]         0000000000000001 0000000000000000 9000000106535880 0000000000000001
[   41.678450]         9000000105291800 0000000000000000 9000000105291838 900000000178e000
[   41.686487]         9000000106c7fd90 9000000106305140 0000000000000001 90000000011e9834
[   41.694523]         00000000ffff0875 90000000011f034c 9000000105291838 9000000105291830
[   41.702561]         0000000000000000 9000000006801440 00000000ffff0875 90000000002d48c0
[   41.710597]         9000000128800001 9000000106305140 9000000105291838 9000000105291838
[   41.718634]         9000000105291830 9000000107811740 9000000105291848 90000000009bf1e0
[   41.726672]         9000000105291830 9000000107811748 2d6b72772d756f69 0000000000343933
[   41.734708]         0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   41.742745]         ...
[   41.745252] Call Trace:
[   42.197868] [<9000000000228848>] _save_fp+0x0/0xd8
[   42.205214] [<90000000011ed468>] __schedule+0x568/0x8d0
[   42.210485] [<90000000011ed834>] schedule+0x64/0xd4
[   42.215411] [<90000000011f434c>] schedule_timeout+0x88/0x188
[   42.221115] [<90000000009c36d0>] io_wqe_worker+0x184/0x350
[   42.226645] [<9000000000221cf0>] ret_from_kernel_thread+0xc/0x9c

This can be easily triggered by ltp testcase syscalls/io_uring02 and it
can also be easily fixed by clearing the FPU/SIMD thread info flags for
kernel threads in copy_thread().

Cc: [email protected]
Reported-by: Qi Hu <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>
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