[syzbot] [bpf?] KASAN: slab-out-of-bounds Read in atomic_ptr_type_ok

[syzbot <syzbot+a5964227adc0f904549c@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    f28214603dc6 Merge branch 'selftests-bpf-move-test_lwt_seg..
git tree:       bpf-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15f84664580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1
dashboard link: https://syzkaller.appspot.com/bug?extid=a5964227adc0f904549c
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=16450ba8580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11f5fa54580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b6b450916744/disk-f2821460.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f67764ad4712/vmlinux-f2821460.xz
kernel image: https://storage.googleapis.com/syzbot-assets/42aedcc506e8/bzImage-f2821460.xz

The issue was bisected to:

commit e24bbad29a8de70bb33c1cabc85bb40e6707572a
Author: Peilin Ye <yepeilin@google.com>
Date:   Tue Mar 4 01:06:13 2025 +0000

    bpf: Introduce load-acquire and store-release instructions

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=154f5074580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=174f5074580000
console output: https://syzkaller.appspot.com/x/log.txt?x=134f5074580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a5964227adc0f904549c@syzkaller.appspotmail.com
Fixes: e24bbad29a8d ("bpf: Introduce load-acquire and store-release instructions")

==================================================================
BUG: KASAN: slab-out-of-bounds in is_ctx_reg kernel/bpf/verifier.c:6185 [inline]
BUG: KASAN: slab-out-of-bounds in atomic_ptr_type_ok+0x3d7/0x550 kernel/bpf/verifier.c:6223
Read of size 4 at addr ffff888141b0d690 by task syz-executor143/5842

CPU: 1 UID: 0 PID: 5842 Comm: syz-executor143 Not tainted 6.14.0-rc3-syzkaller-gf28214603dc6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 is_ctx_reg kernel/bpf/verifier.c:6185 [inline]
 atomic_ptr_type_ok+0x3d7/0x550 kernel/bpf/verifier.c:6223
 check_atomic_store kernel/bpf/verifier.c:7804 [inline]
 check_atomic kernel/bpf/verifier.c:7841 [inline]
 do_check+0x89dd/0xedd0 kernel/bpf/verifier.c:19334
 do_check_common+0x1678/0x2080 kernel/bpf/verifier.c:22600
 do_check_main kernel/bpf/verifier.c:22691 [inline]
 bpf_check+0x165c8/0x1cca0 kernel/bpf/verifier.c:23821
 bpf_prog_load+0x1664/0x20e0 kernel/bpf/syscall.c:2967
 __sys_bpf+0x4ea/0x820 kernel/bpf/syscall.c:5811
 __do_sys_bpf kernel/bpf/syscall.c:5918 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5916 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5916
 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: 0033:0x7fa3ac86bab9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe50fff5f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa3ac86bab9
RDX: 0000000000000094 RSI: 00004000000009c0 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Allocated by task 5842:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4325
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 do_check_common+0x1ec/0x2080 kernel/bpf/verifier.c:22499
 do_check_main kernel/bpf/verifier.c:22691 [inline]
 bpf_check+0x165c8/0x1cca0 kernel/bpf/verifier.c:23821
 bpf_prog_load+0x1664/0x20e0 kernel/bpf/syscall.c:2967
 __sys_bpf+0x4ea/0x820 kernel/bpf/syscall.c:5811
 __do_sys_bpf kernel/bpf/syscall.c:5918 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5916 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5916
 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

The buggy address belongs to the object at ffff888141b0d000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 312 bytes to the right of
 allocated 1368-byte region [ffff888141b0d000, ffff888141b0d558)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x141b08
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801b042000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801b042000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea000506c201 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 8909973200, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1585
 prep_new_page mm/page_alloc.c:1593 [inline]
 get_page_from_freelist+0x3a8c/0x3c20 mm/page_alloc.c:3538
 __alloc_frozen_pages_noprof+0x264/0x580 mm/page_alloc.c:4805
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 __kmalloc_cache_noprof+0x27b/0x390 mm/slub.c:4320
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 virtio_pci_probe+0x54/0x340 drivers/virtio/virtio_pci_common.c:689
 local_pci_probe drivers/pci/pci-driver.c:324 [inline]
 pci_call_probe drivers/pci/pci-driver.c:392 [inline]
 __pci_device_probe drivers/pci/pci-driver.c:417 [inline]
 pci_device_probe+0x6c5/0xa10 drivers/pci/pci-driver.c:451
 really_probe+0x2b9/0xad0 drivers/base/dd.c:658
 __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
 driver_probe_device+0x50/0x430 drivers/base/dd.c:830
 __driver_attach+0x45f/0x710 drivers/base/dd.c:1216
 bus_for_each_dev+0x239/0x2b0 drivers/base/bus.c:370
 bus_add_driver+0x346/0x670 drivers/base/bus.c:678
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888141b0d580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888141b0d600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888141b0d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff888141b0d700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888141b0d780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup