[moderation] [cgroups?] [mm?] KASAN: wild-memory-access Read in lookup_swap_cgroup_id (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1f97d9dcf536 Merge tag 'vfio-v6.19-rc8' of https://github...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16c2c694580000
kernel config: https://syzkaller.appspot.com/x/.config?x=151a39927f1e10b4
dashboard link: https://syzkaller.appspot.com/bug?extid=4eebf44512a34b1f6996
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [ak...@linux-foundation.org cgr...@vger.kernel.org han...@cmpxchg.org linux-...@vger.kernel.org linu...@kvack.org mho...@kernel.org muchu...@linux.dev roman.g...@linux.dev shakee...@linux.dev]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7f4ad52eb61d/disk-1f97d9dc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/10a4de2d9128/vmlinux-1f97d9dc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b6db479fc395/bzImage-1f97d9dc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4eebf4...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: wild-memory-access in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: wild-memory-access in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: wild-memory-access in __swap_cgroup_id_lookup mm/swap_cgroup.c:28 [inline]
BUG: KASAN: wild-memory-access in lookup_swap_cgroup_id+0x8b/0xf0 mm/swap_cgroup.c:127
Read of size 4 at addr 0007fffffffffffc by task syz.5.1657/10291

CPU: 1 UID: 0 PID: 10291 Comm: syz.5.1657 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
kasan_report+0x117/0x150 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
instrument_atomic_read include/linux/instrumented.h:68 [inline]
atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
__swap_cgroup_id_lookup mm/swap_cgroup.c:28 [inline]
lookup_swap_cgroup_id+0x8b/0xf0 mm/swap_cgroup.c:127
swap_pte_batch+0x12d/0x320 mm/internal.h:390
zap_nonpresent_ptes mm/memory.c:1749 [inline]
do_zap_pte_range mm/memory.c:1818 [inline]
zap_pte_range mm/memory.c:1858 [inline]
zap_pmd_range mm/memory.c:1950 [inline]
zap_pud_range mm/memory.c:1978 [inline]
zap_p4d_range mm/memory.c:1999 [inline]
unmap_page_range+0x1416/0x3cd0 mm/memory.c:2020
unmap_single_vma mm/memory.c:2062 [inline]
unmap_vmas+0x3c0/0x5c0 mm/memory.c:2104
exit_mmap+0x251/0xb30 mm/mmap.c:1277
__mmput+0xcb/0x3d0 kernel/fork.c:1173
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x62e/0x2320 kernel/exit.c:959
do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
__do_sys_exit_group kernel/exit.c:1123 [inline]
__se_sys_exit_group kernel/exit.c:1121 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fec3e27aeb9
Code: Unable to access opcode bytes at 0x7fec3e27ae8f.
RSP: 002b:00007ffecb329f38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fec3e27aeb9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffecb329f9c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000103
R13: 00000000000927c0 R14: 000000000003d3cc R15: 00007ffecb329ff0
</TASK>
==================================================================


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