Re: [syzbot] [bcachefs] general protection fault in bioset_exit (2)

syzbot
2025-02-17T02:11:19Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 224e74511041 Merge tag 'kbuild-fixes-v6.14-2' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169b5bf8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e55cabe422b4fcaf
dashboard link: https://syzkaller.appspot.com/bug?extid=76f13f2acac84df26aae
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14e8b5a4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1155a898580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6b4272577622/disk-224e7451.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ec492843be2b/vmlinux-224e7451.xz
kernel image: https://storage.googleapis.com/syzbot-assets/013e7903deef/bzImage-224e7451.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/6b2a19ba3037/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+76f13f2acac84df26aae@syzkaller.appspotmail.com

bcachefs (loop4): shutting down
bcachefs (loop4): shutdown complete
BUG: unable to handle page fault for address: 0000000000003906
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 UID: 0 PID: 5943 Comm: syz-executor233 Not tainted 6.14.0-rc2-syzkaller-00390-g224e74511041 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:qlist_move_cache+0x6a/0x140 mm/kasan/quarantine.c:302
Code: 00 00 00 00 48 8d 47 08 48 89 44 24 18 48 8d 47 10 48 89 44 24 10 48 8d 46 08 48 89 44 24 08 48 8d 46 10 48 89 04 24 4c 89 eb <4d> 8b 6d 00 48 89 df e8 7a 25 48 ff 48 c1 e8 06 48 83 e0 c0 48 8b
RSP: 0000:ffffc900045bf7b0 EFLAGS: 00010006
RAX: 00000000000002c0 RBX: 0000000000003906 RCX: ffffffff9a680288
RDX: ffffffff9a680290 RSI: ffff888064500258 RDI: 0000000000000000
RBP: ffffea0000000000 R08: ffffffff816eac3c R09: fffff520008b7edc
R10: dffffc0000000000 R11: fffff520008b7edc R12: ffffffff9a680280
R13: 0000000000003906 R14: ffffc900045bf808 R15: ffff88814cdb2500
FS: 00007fe4bd5596c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000003906 CR3: 0000000076ddc000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
kasan_quarantine_remove_cache+0x10b/0x180 mm/kasan/quarantine.c:370
kmem_cache_destroy+0x6e/0x160 mm/slab_common.c:528
bio_put_slab block/bio.c:155 [inline]
bioset_exit+0x54e/0x650 block/bio.c:1662
bch2_fs_fs_io_direct_exit+0x19/0x30 fs/bcachefs/fs-io-direct.c:676
__bch2_fs_free fs/bcachefs/super.c:558 [inline]
bch2_fs_release+0x1a9/0x7b0 fs/bcachefs/super.c:624
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x22f/0x480 lib/kobject.c:737
bch2_fs_get_tree+0xdee/0x17a0 fs/bcachefs/fs.c:2299
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3560
do_mount fs/namespace.c:3900 [inline]
__do_sys_mount fs/namespace.c:4111 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe4bddb482a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 7e 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4bd558fd8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe4bd558ff0 RCX: 00007fe4bddb482a
RDX: 00004000000058c0 RSI: 0000400000005900 RDI: 00007fe4bd558ff0
RBP: 0000400000005900 R08: 00007fe4bd559030 R09: 000000000000590c
R10: 0000000000010000 R11: 0000000000000282 R12: 00004000000058c0
R13: 00007fe4bd559030 R14: 0000000000000003 R15: 0000000000010000
</TASK>
Modules linked in:
CR2: 0000000000003906
---[ end trace 0000000000000000 ]---
RIP: 0010:qlist_move_cache+0x6a/0x140 mm/kasan/quarantine.c:302
Code: 00 00 00 00 48 8d 47 08 48 89 44 24 18 48 8d 47 10 48 89 44 24 10 48 8d 46 08 48 89 44 24 08 48 8d 46 10 48 89 04 24 4c 89 eb <4d> 8b 6d 00 48 89 df e8 7a 25 48 ff 48 c1 e8 06 48 83 e0 c0 48 8b
RSP: 0000:ffffc900045bf7b0 EFLAGS: 00010006
RAX: 00000000000002c0 RBX: 0000000000003906 RCX: ffffffff9a680288
RDX: ffffffff9a680290 RSI: ffff888064500258 RDI: 0000000000000000
RBP: ffffea0000000000 R08: ffffffff816eac3c R09: fffff520008b7edc
R10: dffffc0000000000 R11: fffff520008b7edc R12: ffffffff9a680280
R13: 0000000000003906 R14: ffffc900045bf808 R15: ffff88814cdb2500
FS: 00007fe4bd5596c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000003906 CR3: 0000000076ddc000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: 48 8d 47 08 lea 0x8(%rdi),%rax
8: 48 89 44 24 18 mov %rax,0x18(%rsp)
d: 48 8d 47 10 lea 0x10(%rdi),%rax
11: 48 89 44 24 10 mov %rax,0x10(%rsp)
16: 48 8d 46 08 lea 0x8(%rsi),%rax
1a: 48 89 44 24 08 mov %rax,0x8(%rsp)
1f: 48 8d 46 10 lea 0x10(%rsi),%rax
23: 48 89 04 24 mov %rax,(%rsp)
27: 4c 89 eb mov %r13,%rbx
* 2a: 4d 8b 6d 00 mov 0x0(%r13),%r13 <-- trapping instruction
2e: 48 89 df mov %rbx,%rdi
31: e8 7a 25 48 ff call 0xff4825b0
36: 48 c1 e8 06 shr $0x6,%rax
3a: 48 83 e0 c0 and $0xffffffffffffffc0,%rax
3e: 48 rex.W
3f: 8b .byte 0x8b

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