[syzbot] [bpf?] [trace?] KASAN: slab-use-after-free Read in bpf_trace_run3 (2)

syzbot
2026-02-26T14:10:21Z

Hello,

syzbot found the following issue on:

HEAD commit: 32a92f8c8932 Convert more 'alloc_obj' cases to default GFP..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10f64152580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2208a171312e89b7
dashboard link: https://syzkaller.appspot.com/bug?extid=9ea7c90be2b24e189592
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16eaa55a580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-32a92f8c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/78386dbc59f1/vmlinux-32a92f8c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b38bbd9a7831/bzImage-32a92f8c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9ea7c90be2b24e189592@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
BUG: KASAN: slab-use-after-free in bpf_trace_run3+0xdd/0x850 kernel/trace/bpf_trace.c:2130
Read of size 8 at addr ffff888054ecb718 by task syz-executor/5447

CPU: 0 UID: 0 PID: 5447 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run3+0xdd/0x850 kernel/trace/bpf_trace.c:2130
__bpf_trace_mmap_lock_acquire_returned+0x17e/0x1d0 include/trace/events/mmap_lock.h:47
__traceiter_mmap_lock_acquire_returned+0x87/0xe0 include/trace/events/mmap_lock.h:47
__do_trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:47 [inline]
trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:47 [inline]
__mmap_lock_do_trace_acquire_returned+0x1a1/0x210 mm/mmap_lock.c:35
__mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:42 [inline]
mmap_write_lock_killable include/linux/mmap_lock.h:557 [inline]
dup_mmap+0x23d/0x1d90 mm/mmap.c:1740
dup_mm kernel/fork.c:1530 [inline]
copy_mm+0x13b/0x4b0 kernel/fork.c:1582
copy_process+0x18b6/0x3cf0 kernel/fork.c:2223
kernel_clone+0x248/0x8e0 kernel/fork.c:2654
__do_sys_clone kernel/fork.c:2795 [inline]
__se_sys_clone kernel/fork.c:2779 [inline]
__x64_sys_clone+0x1b6/0x230 kernel/fork.c:2779
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f392a1c50d2
Code: 89 e7 e8 b1 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007fffdffb7f00 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fffdffb7f00 RCX: 00007f392a1c50d2
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007fffdffb808c R08: 0000000000000000 R09: 0000000000000000
R10: 0000555578a147d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 000000000002f577 R15: 00007fffdffb80e0
</TASK>

Allocated by task 5916:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5339
kmalloc_noprof include/linux/slab.h:962 [inline]
kzalloc_noprof include/linux/slab.h:1200 [inline]
bpf_raw_tp_link_attach+0x278/0x700 kernel/bpf/syscall.c:4264
bpf_raw_tracepoint_open+0x1b2/0x220 kernel/bpf/syscall.c:4312
__sys_bpf+0x846/0x950 kernel/bpf/syscall.c:6270
__do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5447:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2687 [inline]
slab_free mm/slub.c:6124 [inline]
kfree+0x1c1/0x630 mm/slub.c:6442
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

Last potentially related work creation:
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3131 [inline]
call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
bpf_link_put_direct kernel/bpf/syscall.c:3323 [inline]
bpf_link_release+0x6b/0x80 kernel/bpf/syscall.c:3330
__fput+0x44f/0xa70 fs/file_table.c:469
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888054ecb700
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 24 bytes inside of
freed 192-byte region [ffff888054ecb700, ffff888054ecb7c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888054ecbd00 pfn:0x54ecb
flags: 0x4fff00000000200(workingset|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000200 ffff88801a8413c0 ffffea0001629850 ffff888030400288
raw: ffff888054ecbd00 000000000010000d 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x1d2cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5909, tgid 5909 (syz.4.241), ts 194010998968, free_ts 194010573612
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_slab_page mm/slub.c:3255 [inline]
allocate_slab+0x77/0x660 mm/slub.c:3444
new_slab mm/slub.c:3502 [inline]
refill_objects+0x331/0x3c0 mm/slub.c:7134
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578
alloc_from_pcs mm/slub.c:4681 [inline]
slab_alloc_node mm/slub.c:4815 [inline]
__kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5334
kmalloc_noprof include/linux/slab.h:962 [inline]
kzalloc_noprof include/linux/slab.h:1200 [inline]
bpf_raw_tp_link_attach+0x278/0x700 kernel/bpf/syscall.c:4264
bpf_raw_tracepoint_open+0x1b2/0x220 kernel/bpf/syscall.c:4312
__sys_bpf+0x846/0x950 kernel/bpf/syscall.c:6270
__do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5913 tgid 5913 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
__free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
vfree+0x25a/0x400 mm/vmalloc.c:3479
bpf_prog_calc_tag+0x315/0x370 kernel/bpf/core.c:335
resolve_pseudo_ldimm64+0xbd/0xc90 kernel/bpf/verifier.c:21701
bpf_check+0x1d83/0x1ce00 kernel/bpf/verifier.c:25958
bpf_prog_load+0x1484/0x1ae0 kernel/bpf/syscall.c:3089
__sys_bpf+0x618/0x950 kernel/bpf/syscall.c:6228
__do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888054ecb600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888054ecb680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888054ecb700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888054ecb780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888054ecb800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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