[moderation] [btrfs?] general protection fault in apply_wqattrs_cleanup

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 29c73fc794c8 Merge tag 'perf-tools-for-v6.10-1-2024-05-21'..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12ead934980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5dd4fde1337a9e18
dashboard link: https://syzkaller.appspot.com/bug?extid=8167362a7ff19ee8471e
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386
CC: [c...@fb.com dst...@suse.com jo...@toxicpanda.com linux...@vger.kernel.org linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-29c73fc7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b5f514c0d3c9/vmlinux-29c73fc7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6701ab154a5b/bzImage-29c73fc7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+816736...@syzkaller.appspotmail.com

BTRFS info (device loop0): first mount of filesystem c9fe44da-de57-406a-8241-57ec7d4412cf
BTRFS info (device loop0): using crc32c (crc32c-intel) checksum algorithm
BTRFS info (device loop0): using free-space-tree
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 2 PID: 5844 Comm: syz-executor.0 Not tainted 6.9.0-syzkaller-11002-g29c73fc794c8 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:put_pwq_unlocked kernel/workqueue.c:1662 [inline]
RIP: 0010:put_pwq_unlocked kernel/workqueue.c:1655 [inline]
RIP: 0010:apply_wqattrs_cleanup.part.0+0xbc/0x2b0 kernel/workqueue.c:5223
Code: dd 28 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f 85 8e 01 00 00 48 8b 5c dd 28 48 85 db 74 41 e8 fb cc 35 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 92 01 00 00 48 8b 3b e8 01 0f 89 09 48 89 df
RSP: 0018:ffffc90007a37780 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc90029801000
RDX: 0000000000040000 RSI: ffffffff8158b455 RDI: ffff888021504740
RBP: ffff888021504700 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000003 R11: 0000000000000000 R12: dffffc0000000000
R13: fffffbfff1a9267d R14: 0000000000000001 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff88802c200000(0063) knlGS:00000000f5e6cb40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f5e6d000 CR3: 0000000055698000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
apply_wqattrs_cleanup kernel/workqueue.c:5222 [inline]
apply_workqueue_attrs_locked+0x9e/0xe0 kernel/workqueue.c:5344
apply_workqueue_attrs kernel/workqueue.c:5374 [inline]
alloc_and_link_pwqs kernel/workqueue.c:5502 [inline]
alloc_workqueue+0x1496/0x1ca0 kernel/workqueue.c:5717
btrfs_init_workqueues fs/btrfs/disk-io.c:2002 [inline]
open_ctree+0x14c5/0x52e0 fs/btrfs/disk-io.c:3362
btrfs_fill_super fs/btrfs/super.c:938 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1855 [inline]
btrfs_get_tree+0x11e9/0x1b90 fs/btrfs/super.c:2081
vfs_get_tree+0x8f/0x380 fs/super.c:1780
fc_mount+0x16/0xc0 fs/namespace.c:1125
btrfs_get_tree_subvol fs/btrfs/super.c:2044 [inline]
btrfs_get_tree+0xa53/0x1b90 fs/btrfs/super.c:2082
vfs_get_tree+0x8f/0x380 fs/super.c:1780
do_new_mount fs/namespace.c:3352 [inline]
path_mount+0x6e1/0x1f10 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount fs/namespace.c:3875 [inline]
__ia32_sys_mount+0x295/0x320 fs/namespace.c:3875
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf727a579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5e6c400 EFLAGS: 00000292 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00000000f5e6c460 RCX: 0000000020005140
RDX: 0000000020005100 RSI: 0000000000000016 RDI: 00000000f5e6c4a0
RBP: 00000000f5e6c460 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:put_pwq_unlocked kernel/workqueue.c:1662 [inline]
RIP: 0010:put_pwq_unlocked kernel/workqueue.c:1655 [inline]
RIP: 0010:apply_wqattrs_cleanup.part.0+0xbc/0x2b0 kernel/workqueue.c:5223
Code: dd 28 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f 85 8e 01 00 00 48 8b 5c dd 28 48 85 db 74 41 e8 fb cc 35 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 92 01 00 00 48 8b 3b e8 01 0f 89 09 48 89 df
RSP: 0018:ffffc90007a37780 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc90029801000
RDX: 0000000000040000 RSI: ffffffff8158b455 RDI: ffff888021504740
RBP: ffff888021504700 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000003 R11: 0000000000000000 R12: dffffc0000000000
R13: fffffbfff1a9267d R14: 0000000000000001 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff88802c200000(0063) knlGS:00000000f5e6cb40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f5e6d000 CR3: 0000000055698000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: dd 28 (bad) (%rax)
2: 48 89 f8 mov %rdi,%rax
5: 48 c1 e8 03 shr $0x3,%rax
9: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1)
e: 0f 85 8e 01 00 00 jne 0x1a2
14: 48 8b 5c dd 28 mov 0x28(%rbp,%rbx,8),%rbx
19: 48 85 db test %rbx,%rbx
1c: 74 41 je 0x5f
1e: e8 fb cc 35 00 call 0x35cd1e
23: 48 89 d8 mov %rbx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 0f 85 92 01 00 00 jne 0x1c7
35: 48 8b 3b mov (%rbx),%rdi
38: e8 01 0f 89 09 call 0x9890f3e
3d: 48 89 df mov %rbx,%rdi


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