[moderation] [kernel?] KASAN: global-out-of-bounds Read in pid_task (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 590b221ed425 Add linux-next specific files for 20250912
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10a20b62580000
kernel config: https://syzkaller.appspot.com/x/.config?x=12a1d1f3a8199632
dashboard link: https://syzkaller.appspot.com/bug?extid=87ba2e47435f2c45ad11
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
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/63a963fc26db/disk-590b221e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0c2013d30830/vmlinux-590b221e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7ee4d3a8e8f6/bzImage-590b221e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+87ba2e...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: global-out-of-bounds in pid_task+0x5a/0x140 kernel/pid.c:418
Read of size 8 at addr ffffffff92c9f918 by task syz.0.83/6399

CPU: 1 UID: 0 PID: 6399 Comm: syz.0.83 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
pid_task+0x5a/0x140 kernel/pid.c:418
dump_holder fs/gfs2/glock.c:2283 [inline]
gfs2_dump_glock+0x10b4/0x1bc0 fs/gfs2/glock.c:2398
gfs2_consist_inode_i+0xf5/0x110 fs/gfs2/util.c:446
gfs2_dirent_scan+0x545/0x690 fs/gfs2/dir.c:-1
gfs2_dirent_search+0x2cb/0x710 fs/gfs2/dir.c:854
gfs2_dir_search+0x4c/0x220 fs/gfs2/dir.c:1651
gfs2_lookupi+0x3d9/0x5a0 fs/gfs2/inode.c:340
__gfs2_lookup+0x8f/0x270 fs/gfs2/inode.c:975
__lookup_slow+0x297/0x3d0 fs/namei.c:1816
lookup_slow+0x53/0x70 fs/namei.c:1833
walk_component+0x2d2/0x400 fs/namei.c:2137
lookup_last fs/namei.c:2638 [inline]
path_lookupat+0x163/0x430 fs/namei.c:2662
filename_lookup+0x212/0x570 fs/namei.c:2691
vfs_statx+0xf8/0x550 fs/stat.c:353
vfs_fstatat+0x118/0x170 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__x64_sys_newfstatat+0x116/0x190 fs/stat.c:536
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f82fe18eba9
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:00007f82ff0a8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007f82fe3d5fa0 RCX: 00007f82fe18eba9
RDX: 0000000000000000 RSI: 0000200000000e80 RDI: ffffffffffffff9c
RBP: 00007f82fe211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000002000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f82fe3d6038 R14: 00007f82fe3d5fa0 R15: 00007ffe8821e178
</TASK>

The buggy address belongs to the variable:
copy_signal.__key.112+0x18/0x20

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12c9f
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00004b27c8 ffffea00004b27c8 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:
ffffffff92c9f800: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
ffffffff92c9f880: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
>ffffffff92c9f900: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
^
ffffffff92c9f980: 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9 00 00 f9 f9
ffffffff92c9fa00: 00 00 f9 f9 00 00 f9 f9 01 f9 f9 f9 00 f9 f9 f9
==================================================================


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