[moderation] [kernel?] KASAN: global-out-of-bounds Read in pid_task (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f817b6dd2b62 Add linux-next specific files for 20250623
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=150f8b70580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f7617ed010d11464
dashboard link: https://syzkaller.appspot.com/bug?extid=c4bb731417769d640cbb
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
CC: [linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/46b566285581/disk-f817b6dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/309821efbf7d/vmlinux-f817b6dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1560804d2fb2/bzImage-f817b6dd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c4bb73...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: global-out-of-bounds in pid_task+0x5a/0x140 kernel/pid.c:418
Read of size 8 at addr ffffffff92a61918 by task syz.5.269/7237

CPU: 0 UID: 0 PID: 7237 Comm: syz.5.269 Not tainted 6.16.0-rc3-next-20250623-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xd2/0x2b0 mm/kasan/report.c:521
kasan_report+0x118/0x150 mm/kasan/report.c:634
pid_task+0x5a/0x140 kernel/pid.c:418
dump_holder fs/gfs2/glock.c:2297 [inline]
gfs2_dump_glock+0x112c/0x1c50 fs/gfs2/glock.c:2414
gfs2_consist_inode_i+0xf5/0x110 fs/gfs2/util.c:457
gfs2_dirent_scan+0x545/0x690 fs/gfs2/dir.c:-1
gfs2_dir_read+0x806/0x1780 fs/gfs2/dir.c:1602
gfs2_readdir+0x14c/0x1b0 fs/gfs2/file.c:116
iterate_dir+0x5af/0x770 fs/readdir.c:108
__do_sys_getdents fs/readdir.c:326 [inline]
__se_sys_getdents+0xe4/0x250 fs/readdir.c:312
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9ac5b8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9ac39f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f9ac5db6080 RCX: 00007f9ac5b8e929
RDX: 00000000000000b8 RSI: 0000200000000680 RDI: 000000000000000b
RBP: 00007f9ac5c10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9ac5db6080 R15: 00007ffcc46508e8
</TASK>

The buggy address belongs to the variable:
copy_signal.__key.111+0x18/0x20

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12a61
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00004a9848 ffffea00004a9848 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
ffffffff92a61800: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
ffffffff92a61880: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
>ffffffff92a61900: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
^
ffffffff92a61980: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
ffffffff92a61a00: 00 00 f9 f9 01 f9 f9 f9 00 f9 f9 f9 01 f9 f9 f9
==================================================================


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[Aleksandr Nogikh]

#syz set subsystems: gfs2

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[syzbot]

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