syzbot


KASAN: stack-out-of-bounds Read in gfs2_file_read_iter (3)

Status: upstream: reported on 2026/06/01 03:40
Reported-by: syzbot+09675e90f1ef60d6ed3d@syzkaller.appspotmail.com
First crash: 4d00h, last: 2d23h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: stack-out-of-bounds Read in gfs2_file_read_iter (2) 17 341 94d 774d 0/3 auto-obsoleted due to no activity on 2026/05/11 16:12
linux-5.15 KASAN: stack-out-of-bounds Read in gfs2_file_read_iter 17 15 992d 1006d 0/3 auto-obsoleted due to no activity on 2023/11/25 16:09

Sample crash report:
gfs2: fsid=syz:syz.0: first mount done, others may mount
==================================================================
BUG: KASAN: stack-out-of-bounds in should_fault_in_pages fs/gfs2/file.c:785 [inline]
BUG: KASAN: stack-out-of-bounds in gfs2_file_read_iter+0x8e1/0xda0 fs/gfs2/file.c:995
Read of size 8 at addr ffffc900050bfd50 by task syz.0.42/4465

CPU: 1 PID: 4465 Comm: syz.0.42 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 should_fault_in_pages fs/gfs2/file.c:785 [inline]
 gfs2_file_read_iter+0x8e1/0xda0 fs/gfs2/file.c:995
 call_read_iter include/linux/fs.h:2167 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x759/0xd60 fs/read_write.c:485
 ksys_read+0x152/0x260 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f57ba843e59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f57b8a9d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f57baabcfa0 RCX: 00007f57ba843e59
RDX: 0000000000002020 RSI: 0000200000001300 RDI: 0000000000000004
RBP: 00007f57ba8d9d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f57baabd038 R14: 00007f57baabcfa0 R15: 00007ffd3ce6e728
 </TASK>


addr ffffc900050bfd50 is located in stack of task syz.0.42/4465 at offset 48 in frame:
 vfs_read+0x0/0xd60

this frame has 3 objects:
 [32, 48) 'iov.i'
 [64, 112) 'kiocb.i'
 [144, 184) 'iter.i'

Memory state around the buggy address:
 ffffc900050bfc00: 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 00 00 00 00
 ffffc900050bfc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900050bfd00: 00 00 00 00 f1 f1 f1 f1 00 00 f2 f2 00 00 00 00
                                                 ^
 ffffc900050bfd80: 00 00 f2 f2 f2 f2 00 00 00 00 00 f3 f3 f3 f3 f3
 ffffc900050bfe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/02 04:51 linux-5.15.y dc027a595035 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: stack-out-of-bounds Read in gfs2_file_read_iter
2026/06/02 04:51 linux-5.15.y dc027a595035 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: stack-out-of-bounds Read in gfs2_file_read_iter
2026/06/01 03:42 linux-5.15.y 241d66fa280c 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: stack-out-of-bounds Read in gfs2_file_read_iter
2026/06/01 03:40 linux-5.15.y 241d66fa280c 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: stack-out-of-bounds Read in gfs2_file_read_iter
* Struck through repros no longer work on HEAD.