[syzbot] general protection fault in submit_bio_checks

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b605fdc54c2b Add linux-next specific files for 20220128
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=150084b8700000
kernel config: https://syzkaller.appspot.com/x/.config?x=da5090473475f3ca
dashboard link: https://syzkaller.appspot.com/bug?extid=2b3f18414c37b42dcc94
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2b3f18...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000002f: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000178-0x000000000000017f]
CPU: 1 PID: 3642 Comm: syz-executor.5 Not tainted 5.17.0-rc1-next-20220128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:blk_throtl_bio block/blk-throttle.h:175 [inline]
RIP: 0010:submit_bio_checks+0x7c0/0x1bf0 block/blk-core.c:765
Code: 08 3c 03 0f 8e 4a 11 00 00 48 b8 00 00 00 00 00 fc ff df 44 8b 6d 10 41 83 e5 01 4a 8d bc 2b 7c 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 09 11 00 00
RSP: 0018:ffffc900028cf680 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000002f RSI: ffffffff83d5f41e RDI: 000000000000017d
RBP: ffff88801e8be500 R08: ffffffff8a241580 R09: 0000000000000000
R10: ffffffff83d5f410 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000fffffffe R15: ffff88801ad9a4cc
FS: 0000555556299400(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fed92bd5ec9 CR3: 000000003b65d000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__submit_bio+0xaf/0x360 block/blk-core.c:802
__submit_bio_noacct_mq block/blk-core.c:881 [inline]
submit_bio_noacct block/blk-core.c:907 [inline]
submit_bio_noacct+0x6c9/0x8a0 block/blk-core.c:896
submit_bio block/blk-core.c:968 [inline]
submit_bio+0x1ea/0x430 block/blk-core.c:926
write_dev_flush fs/btrfs/disk-io.c:4243 [inline]
barrier_all_devices fs/btrfs/disk-io.c:4293 [inline]
write_all_supers+0x3038/0x4440 fs/btrfs/disk-io.c:4388
btrfs_commit_transaction+0x1be3/0x3180 fs/btrfs/transaction.c:2362
btrfs_commit_super+0xc1/0x100 fs/btrfs/disk-io.c:4562
close_ctree+0x314/0xccc fs/btrfs/disk-io.c:4671
generic_shutdown_super+0x14c/0x400 fs/super.c:462
kill_anon_super+0x36/0x60 fs/super.c:1056
btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2365
deactivate_locked_super+0x94/0x160 fs/super.c:332
deactivate_super+0xad/0xd0 fs/super.c:363
cleanup_mnt+0x3a2/0x540 fs/namespace.c:1159
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fe814b274c7
Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe14eb15c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe814b274c7
RDX: 00007ffe14eb169b RSI: 000000000000000a RDI: 00007ffe14eb1690
RBP: 00007ffe14eb1690 R08: 00000000ffffffff R09: 00007ffe14eb1460
R10: 000055555629a8b3 R11: 0000000000000246 R12: 00007fe814b7f1ea
R13: 00007ffe14eb2750 R14: 000055555629a810 R15: 00007ffe14eb2790
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:blk_throtl_bio block/blk-throttle.h:175 [inline]
RIP: 0010:submit_bio_checks+0x7c0/0x1bf0 block/blk-core.c:765
Code: 08 3c 03 0f 8e 4a 11 00 00 48 b8 00 00 00 00 00 fc ff df 44 8b 6d 10 41 83 e5 01 4a 8d bc 2b 7c 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 09 11 00 00
RSP: 0018:ffffc900028cf680 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000002f RSI: ffffffff83d5f41e RDI: 000000000000017d
RBP: ffff88801e8be500 R08: ffffffff8a241580 R09: 0000000000000000
R10: ffffffff83d5f410 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000fffffffe R15: ffff88801ad9a4cc
FS: 0000555556299400(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeece8b278 CR3: 000000003b65d000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 08 3c 03 or %bh,(%rbx,%rax,1)
3: 0f 8e 4a 11 00 00 jle 0x1153
9: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
10: fc ff df
13: 44 8b 6d 10 mov 0x10(%rbp),%r13d
17: 41 83 e5 01 and $0x1,%r13d
1b: 4a 8d bc 2b 7c 01 00 lea 0x17c(%rbx,%r13,1),%rdi
22: 00
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 48 89 fa mov %rdi,%rdx
31: 83 e2 07 and $0x7,%edx
34: 38 d0 cmp %dl,%al
36: 7f 08 jg 0x40
38: 84 c0 test %al,%al
3a: 0f 85 09 11 00 00 jne 0x1149


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 2d3d8c7643a5 Add linux-next specific files for 20220203
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14c0c8dc700000
kernel config: https://syzkaller.appspot.com/x/.config?x=27a9abf2c11167c7

dashboard link: https://syzkaller.appspot.com/bug?extid=2b3f18414c37b42dcc94
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14635480700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10eb2d14700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2b3f18...@syzkaller.appspotmail.com

BTRFS info (device loop0): disk space caching is enabled
BTRFS info (device loop0): has skinny extents
BTRFS info (device loop0): enabling ssd optimizations

general protection fault, probably for non-canonical address 0xdffffc000000002f: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000178-0x000000000000017f]

CPU: 0 PID: 3586 Comm: syz-executor095 Not tainted 5.17.0-rc2-next-20220203-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:blk_throtl_bio block/blk-throttle.h:175 [inline]
RIP: 0010:submit_bio_checks+0x7c0/0x1bf0 block/blk-core.c:765
Code: 08 3c 03 0f 8e 4a 11 00 00 48 b8 00 00 00 00 00 fc ff df 44 8b 6d 10 41 83 e5 01 4a 8d bc 2b 7c 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 09 11 00 00

RSP: 0018:ffffc9000293f278 EFLAGS: 00010203

RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000

RDX: 000000000000002f RSI: ffffffff83d5d9de RDI: 000000000000017d
RBP: ffff888014fbd300 R08: ffffffff8a044f00 R09: 0000000000000000
R10: ffffffff83d5d9d0 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000fffffffe R15: ffff88801a2be93c
FS: 0000555555975300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f9789f79668 CR3: 00000000145d1000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__submit_bio+0xaf/0x360 block/blk-core.c:802
__submit_bio_noacct_mq block/blk-core.c:881 [inline]
submit_bio_noacct block/blk-core.c:907 [inline]
submit_bio_noacct+0x6c9/0x8a0 block/blk-core.c:896
submit_bio block/blk-core.c:968 [inline]
submit_bio+0x1ea/0x430 block/blk-core.c:926
write_dev_flush fs/btrfs/disk-io.c:4243 [inline]
barrier_all_devices fs/btrfs/disk-io.c:4293 [inline]
write_all_supers+0x3038/0x4440 fs/btrfs/disk-io.c:4388
btrfs_commit_transaction+0x1be3/0x3180 fs/btrfs/transaction.c:2362
btrfs_commit_super+0xc1/0x100 fs/btrfs/disk-io.c:4562
close_ctree+0x314/0xccc fs/btrfs/disk-io.c:4671

btrfs_fill_super fs/btrfs/super.c:1400 [inline]
btrfs_mount_root.cold+0xb1/0x162 fs/btrfs/super.c:1744
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1497
fc_mount fs/namespace.c:1016 [inline]
vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1046
vfs_kern_mount+0x3c/0x60 fs/namespace.c:1033
btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1804
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1497
do_new_mount fs/namespace.c:3012 [inline]
path_mount+0x1320/0x1fa0 fs/namespace.c:3342
do_mount fs/namespace.c:3355 [inline]
__do_sys_mount fs/namespace.c:3563 [inline]
__se_sys_mount fs/namespace.c:3540 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3540
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7ff53f71fd8a
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeaf8661f8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffeaf866250 RCX: 00007ff53f71fd8a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffeaf866210
RBP: 00007ffeaf866210 R08: 00007ffeaf866250 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000282 R12: 0000000020000f50
R13: 0000000000000003 R14: 0000000000000004 R15: 000000000000008e

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:blk_throtl_bio block/blk-throttle.h:175 [inline]
RIP: 0010:submit_bio_checks+0x7c0/0x1bf0 block/blk-core.c:765
Code: 08 3c 03 0f 8e 4a 11 00 00 48 b8 00 00 00 00 00 fc ff df 44 8b 6d 10 41 83 e5 01 4a 8d bc 2b 7c 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 09 11 00 00

RSP: 0018:ffffc9000293f278 EFLAGS: 00010203

RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000

RDX: 000000000000002f RSI: ffffffff83d5d9de RDI: 000000000000017d
RBP: ffff888014fbd300 R08: ffffffff8a044f00 R09: 0000000000000000
R10: ffffffff83d5d9d0 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000fffffffe R15: ffff88801a2be93c
FS: 0000555555975300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fab1d1bfe28 CR3: 00000000145d1000 CR4: 00000000003506e0

[syzbot]

syzbot has bisected this issue to:

commit a7c50c940477bae89fb2b4f51bd969a2d95d7512
Author: Christoph Hellwig <h...@lst.de>
Date: Mon Jan 24 09:11:07 2022 +0000

block: pass a block_device and opf to bio_reset

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12b4f1cc700000
start commit: 2d3d8c7643a5 Add linux-next specific files for 20220203
git tree: linux-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=11b4f1cc700000
console output: https://syzkaller.appspot.com/x/log.txt?x=16b4f1cc700000

kernel config: https://syzkaller.appspot.com/x/.config?x=27a9abf2c11167c7
dashboard link: https://syzkaller.appspot.com/bug?extid=2b3f18414c37b42dcc94

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14635480700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10eb2d14700000

Reported-by: syzbot+2b3f18...@syzkaller.appspotmail.com
Fixes: a7c50c940477 ("block: pass a block_device and opf to bio_reset")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Jens Axboe]

Christoph, looks like an issue with replacing bio_set_dev() with just
assigning bio->bi_bdev in bio_reset(). The latter does not associate the
blkcg, for example, which is what is causing this oops.

--
Jens Axboe

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

block/bio.c:313:18: error: expected ')' before 'bio_associate_blkg'
block/bio.c:316:1: error: expected expression before '}' token


Tested on:

commit: cfd1b68d block: call bio_associate_blkg from bio_reset
git tree: git://git.infradead.org/users/hch/block.git bio-reset-fix

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+2b3f18...@syzkaller.appspotmail.com

Tested on:

commit: 07154d8c block: call bio_associate_blkg from bio_reset

git tree: git://git.infradead.org/users/hch/block.git bio-reset-fix

kernel config: https://syzkaller.appspot.com/x/.config?x=7160f560bcd429e5

dashboard link: https://syzkaller.appspot.com/bug?extid=2b3f18414c37b42dcc94
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Note: testing is done by a robot and is best-effort only.