general protection fault in bdevname

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9d49fb30 ANDROID: GKI: Add support for a GKI_DEFCONFIG_FRA..
git tree: android12-5.4
console output: https://syzkaller.appspot.com/x/log.txt?x=166a562ed00000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf50317962957906
dashboard link: https://syzkaller.appspot.com/bug?extid=e5cb85a7b902a4de1d71
compiler: Debian clang version 11.0.1-2

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+e5cb85...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 2155 Comm: kmmpd-loop0 Not tainted 5.4.113-syzkaller-00286-g9d49fb308497 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bdevname+0x2d/0x160 block/partition-generic.c:49
Code: 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 81 9d 44 ff 48 8d bb 80 00 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 05 e8 67 52 73 ff 4c 8b ab 80 00 00 00 48 83 c3
RSP: 0018:ffff88819e75fd68 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000000 RCX: ffff8881e3536e40
RDX: 0000000000000000 RSI: ffff88819da92050 RDI: 0000000000000080
RBP: ffff88819e75ff00 R08: ffffffff81c959f7 R09: ffffed103cf8c211
R10: ffffed103cf8c211 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88819da92050 R15: 000000000000000a
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000228fb38 CR3: 00000001ac864000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kmmpd+0x239/0xa40 fs/ext4/mmp.c:158
kthread+0x30f/0x330 kernel/kthread.c:268
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace 3e2e4c0cd493a1dd ]---
RIP: 0010:bdevname+0x2d/0x160 block/partition-generic.c:49
Code: 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 81 9d 44 ff 48 8d bb 80 00 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 05 e8 67 52 73 ff 4c 8b ab 80 00 00 00 48 83 c3
RSP: 0018:ffff88819e75fd68 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000000 RCX: ffff8881e3536e40
RDX: 0000000000000000 RSI: ffff88819da92050 RDI: 0000000000000080
RBP: ffff88819e75ff00 R08: ffffffff81c959f7 R09: ffffed103cf8c211
R10: ffffed103cf8c211 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88819da92050 R15: 000000000000000a
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6dcb749ab CR3: 00000001ac864000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.