[syzbot] [ocfs2?] general protection fault in ocfs2_buffer_cached

syzbot
2024-08-15T10:47:23Z

Hello,

syzbot found the following issue on:

HEAD commit: d07b43284ab3 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=126c2aa3980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7229118d88b4a71b
dashboard link: https://syzkaller.appspot.com/bug?extid=adfd64e93c46b99c957e
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=1206cdd3980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13cfea91980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-d07b4328.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/91ceec6e19d3/vmlinux-d07b4328.xz
kernel image: https://storage.googleapis.com/syzbot-assets/be11646b0c05/bzImage-d07b4328.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/90c0e9dcfbf9/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+adfd64e93c46b99c957e@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
(syz-executor178,5091,0):ocfs2_read_blocks:240 ERROR: status = -12
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 UID: 0 PID: 5091 Comm: syz-executor178 Not tainted 6.11.0-rc3-syzkaller-00060-gd07b43284ab3 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ocfs2_buffer_cached+0xcb/0x840 fs/ocfs2/uptodate.c:237
Code: eb b2 65 fe 4c 89 7c 24 20 4c 8b 5d 00 48 89 5c 24 08 48 89 df 41 ff d3 66 90 48 89 44 24 18 49 83 c5 18 4d 89 ec 49 c1 ec 03 <43> 80 3c 34 00 74 08 4c 89 ef e8 b6 b2 65 fe 49 8b 55 00 48 8b 44
RSP: 0018:ffffc9000b01e620 EFLAGS: 00010206
RAX: 0000000000000012 RBX: ffff88805f1faa70 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88805f1faa70
RBP: ffffffff8c48fcc0 R08: 0000000000000003 R09: fffff52001603cb4
R10: dffffc0000000000 R11: ffffffff8385d210 R12: 0000000000000003
R13: 0000000000000018 R14: dffffc0000000000 R15: 1ffff1100be3f54e
FS: 00005555632e5380(0000) GS:ffff888020800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc970f4c08 CR3: 0000000036024000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ocfs2_set_buffer_uptodate+0xa1/0x1350 fs/ocfs2/uptodate.c:474
ocfs2_read_blocks+0x103e/0x1620 fs/ocfs2/buffer_head_io.c:392
ocfs2_read_virt_blocks+0x4c8/0xa50 fs/ocfs2/extent_map.c:1010
ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
ocfs2_find_entry+0x43b/0x2780 fs/ocfs2/dir.c:1080
ocfs2_find_files_on_disk+0xff/0x360 fs/ocfs2/dir.c:1980
ocfs2_lookup_ino_from_name+0xb1/0x1e0 fs/ocfs2/dir.c:2002
_ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
ocfs2_get_system_file_inode+0x305/0x7b0 fs/ocfs2/sysfile.c:112
ocfs2_init_global_system_inodes+0x32c/0x730 fs/ocfs2/super.c:457
ocfs2_initialize_super fs/ocfs2/super.c:2250 [inline]
ocfs2_fill_super+0x3068/0x5880 fs/ocfs2/super.c:994
mount_bdev+0x20a/0x2d0 fs/super.c:1679
legacy_get_tree+0xee/0x190 fs/fs_context.c:662
vfs_get_tree+0x90/0x2a0 fs/super.c:1800
do_new_mount+0x2be/0xb40 fs/namespace.c:3472
do_mount fs/namespace.c:3812 [inline]
__do_sys_mount fs/namespace.c:4020 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3997
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: 0033:0x7f4945e4ddea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdf618e318 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdf618e330 RCX: 00007f4945e4ddea
RDX: 0000000020004480 RSI: 00000000200044c0 RDI: 00007ffdf618e330
RBP: 0000000000000004 R08: 00007ffdf618e370 R09: 000000000000446f
R10: 0000000002800400 R11: 0000000000000282 R12: 0000000002800400
R13: 00007ffdf618e370 R14: 0000000000000003 R15: 0000000001000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ocfs2_buffer_cached+0xcb/0x840 fs/ocfs2/uptodate.c:237
Code: eb b2 65 fe 4c 89 7c 24 20 4c 8b 5d 00 48 89 5c 24 08 48 89 df 41 ff d3 66 90 48 89 44 24 18 49 83 c5 18 4d 89 ec 49 c1 ec 03 <43> 80 3c 34 00 74 08 4c 89 ef e8 b6 b2 65 fe 49 8b 55 00 48 8b 44
RSP: 0018:ffffc9000b01e620 EFLAGS: 00010206
RAX: 0000000000000012 RBX: ffff88805f1faa70 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88805f1faa70
RBP: ffffffff8c48fcc0 R08: 0000000000000003 R09: fffff52001603cb4
R10: dffffc0000000000 R11: ffffffff8385d210 R12: 0000000000000003
R13: 0000000000000018 R14: dffffc0000000000 R15: 1ffff1100be3f54e
FS: 00005555632e5380(0000) GS:ffff888020800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc970f4c08 CR3: 0000000036024000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: eb b2 jmp 0xffffffb4
2: 65 fe 4c 89 7c decb %gs:0x7c(%rcx,%rcx,4)
7: 24 20 and $0x20,%al
9: 4c 8b 5d 00 mov 0x0(%rbp),%r11
d: 48 89 5c 24 08 mov %rbx,0x8(%rsp)
12: 48 89 df mov %rbx,%rdi
15: 41 ff d3 call *%r11
18: 66 90 xchg %ax,%ax
1a: 48 89 44 24 18 mov %rax,0x18(%rsp)
1f: 49 83 c5 18 add $0x18,%r13
23: 4d 89 ec mov %r13,%r12
26: 49 c1 ec 03 shr $0x3,%r12
* 2a: 43 80 3c 34 00 cmpb $0x0,(%r12,%r14,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 ef mov %r13,%rdi
34: e8 b6 b2 65 fe call 0xfe65b2ef
39: 49 8b 55 00 mov 0x0(%r13),%rdx
3d: 48 rex.W
3e: 8b .byte 0x8b
3f: 44 rex.R

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