general protection fault in blk_cgroup_bio_start

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syzbot

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Jan 29, 2023, 8:07:42 AM1/29/23
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Hello,

syzbot found the following issue on:

HEAD commit: 2a48216cff7a Merge git://git.kernel.org/pub/scm/linux/kern..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=112bc815480000
kernel config: https://syzkaller.appspot.com/x/.config?x=899d86a7610a0ea0
dashboard link: https://syzkaller.appspot.com/bug?extid=b75f58f484cce0cf5b01
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [ax...@kernel.dk cgr...@vger.kernel.org jo...@toxicpanda.com linux...@vger.kernel.org linux-...@vger.kernel.org t...@kernel.org net...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/48d467497cd0/disk-2a48216c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ec0524351494/vmlinux-2a48216c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a42125d32b7c/bzImage-2a48216c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b75f58...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 0 PID: 15668 Comm: syz-executor.5 Not tainted 6.2.0-rc4-syzkaller-00221-g2a48216cff7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:__ref_is_percpu include/linux/percpu-refcount.h:174 [inline]
RIP: 0010:percpu_ref_get_many include/linux/percpu-refcount.h:204 [inline]
RIP: 0010:percpu_ref_get include/linux/percpu-refcount.h:222 [inline]
RIP: 0010:blk_cgroup_bio_start+0x411/0x6b0 block/blk-cgroup.c:2023
Code: 89 c6 e8 32 ab 89 fd 84 db 58 0f 84 f0 00 00 00 e8 b4 ae 89 fd 48 8d 7d 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 7f 02 00 00 48 8b 5d 38 31 ff 49 89 dc 41 83 e4
RSP: 0018:ffffc90004ddf020 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc9000de1b000
RDX: 0000000000000007 RSI: ffffffff83f7b3bc RDI: 0000000000000038
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000094001 R12: ffffe8ffffc9da58
R13: 0000000000000000 R14: ffff8880481f1000 R15: 0000000000000000
FS: 00007fe7c01dd700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3a06352920 CR3: 000000002b2da000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
submit_bio_noacct+0x6d2/0x1e70 block/blk-core.c:792
submit_bio block/blk-core.c:838 [inline]
submit_bio+0x8f/0x1c0 block/blk-core.c:826
ext4_io_submit+0xa6/0x140 fs/ext4/page-io.c:378
ext4_do_writepages+0x1542/0x36e0 fs/ext4/inode.c:2897
ext4_writepages+0x27c/0x5a0 fs/ext4/inode.c:2965
do_writepages+0x1af/0x690 mm/page-writeback.c:2581
filemap_fdatawrite_wbc mm/filemap.c:388 [inline]
filemap_fdatawrite_wbc+0x147/0x1b0 mm/filemap.c:378
__filemap_fdatawrite_range+0xb8/0xf0 mm/filemap.c:421
filemap_write_and_wait_range mm/filemap.c:674 [inline]
filemap_write_and_wait_range+0xa1/0x120 mm/filemap.c:665
__iomap_dio_rw+0x5ea/0x1cd0 fs/iomap/direct-io.c:572
iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:689
ext4_dio_read_iter fs/ext4/file.c:94 [inline]
ext4_file_read_iter+0x4be/0x690 fs/ext4/file.c:145
call_read_iter include/linux/fs.h:2183 [inline]
generic_file_splice_read+0x182/0x4b0 fs/splice.c:309
do_splice_to+0x1b9/0x240 fs/splice.c:793
splice_direct_to_actor+0x2ab/0x8a0 fs/splice.c:865
do_splice_direct+0x1ab/0x280 fs/splice.c:974
do_sendfile+0xb19/0x1270 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__x64_sys_sendfile64+0x1d0/0x210 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe7c168c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007fe7c01dd168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fe7c17ac050 RCX: 00007fe7c168c0c9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000008
RBP: 00007fe7c16e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 000000010000a006 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd38da38cf R14: 00007fe7c01dd300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__ref_is_percpu include/linux/percpu-refcount.h:174 [inline]
RIP: 0010:percpu_ref_get_many include/linux/percpu-refcount.h:204 [inline]
RIP: 0010:percpu_ref_get include/linux/percpu-refcount.h:222 [inline]
RIP: 0010:blk_cgroup_bio_start+0x411/0x6b0 block/blk-cgroup.c:2023
Code: 89 c6 e8 32 ab 89 fd 84 db 58 0f 84 f0 00 00 00 e8 b4 ae 89 fd 48 8d 7d 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 7f 02 00 00 48 8b 5d 38 31 ff 49 89 dc 41 83 e4
RSP: 0018:ffffc90004ddf020 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc9000de1b000
RDX: 0000000000000007 RSI: ffffffff83f7b3bc RDI: 0000000000000038
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000094001 R12: ffffe8ffffc9da58
R13: 0000000000000000 R14: ffff8880481f1000 R15: 0000000000000000
FS: 00007fe7c01dd700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3a06352920 CR3: 000000002b2da000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 89 c6 mov %eax,%esi
2: e8 32 ab 89 fd callq 0xfd89ab39
7: 84 db test %bl,%bl
9: 58 pop %rax
a: 0f 84 f0 00 00 00 je 0x100
10: e8 b4 ae 89 fd callq 0xfd89aec9
15: 48 8d 7d 38 lea 0x38(%rbp),%rdi
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 7f 02 00 00 jne 0x2b3
34: 48 8b 5d 38 mov 0x38(%rbp),%rbx
38: 31 ff xor %edi,%edi
3a: 49 89 dc mov %rbx,%r12
3d: 41 rex.B
3e: 83 .byte 0x83
3f: e4 .byte 0xe4


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syzbot

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Jul 24, 2023, 10:41:52 AM7/24/23
to syzkaller-upst...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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