KASAN: slab-use-after-free Read in bpf_trace_run9

Status: upstream: reported C repro on 2026/03/03 18:24
Subsystems: bpf trace
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+b4c5ad098c821bf8d8bc@syzkaller.appspotmail.com
First crash: 159d, last: 159d
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
cdedd57b assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Read in bpf_trace_run9 2026/05/19 20:47 2026/05/19 20:47 2026/05/19 21:26 1d9407ad
583251aa patching 💥 KASAN: slab-use-after-free Read in bpf_trace_run9 2026/03/18 14:16 2026/03/18 14:16 2026/03/18 14:26 f84caa2f
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[syzbot] [bpf?] [trace?] KASAN: slab-use-after-free Read in bpf_trace_run4 (2) 1 (2) 2026/03/20 02:41
[PATCH v2] bpf: Fix use-after-free in __bpf_trace_run() 3 (3) 2026/03/05 07:16
[syzbot] [bpf?] [trace?] KASAN: slab-use-after-free Read in bpf_trace_run3 (2) 4 (9) 2026/03/04 08:07
[PATCH] bpf: Fix use-after-free in __bpf_trace_run() 2 (2) 2026/03/04 07:54
[syzbot] [bpf?] [trace?] KASAN: slab-use-after-free Read in bpf_trace_run9 2 (4) 2026/03/04 04:06
▶ ▼ Last patch testing requests (11)
Created Duration User Patch Repo Result
2026/08/01 04:49 21m retest repro upstream error
2026/08/01 04:49 21m retest repro upstream error
2026/08/01 04:49 21m retest repro upstream error
2026/08/01 04:49 20m retest repro upstream error
2026/08/01 03:24 22m retest repro upstream error
2026/05/23 02:39 21m retest repro upstream error
2026/05/23 02:39 21m retest repro upstream error
2026/05/23 02:39 21m retest repro upstream error
2026/05/23 02:39 21m retest repro upstream error
2026/05/23 02:39 22m retest repro upstream error
2026/03/04 03:38 27m wangqing7171@gmail.com patch upstream OK log

Sample crash report:
==================================================================
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_run9+0x13b/0x8c0 kernel/trace/bpf_trace.c:2136
Read of size 8 at addr ffff888039269618 by task syz.5.56/5665

CPU: 0 UID: 0 PID: 5665 Comm: syz.5.56 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_run9+0x13b/0x8c0 kernel/trace/bpf_trace.c:2136
 __bpf_trace_virtio_transport_alloc_pkt+0x3a5/0x410 include/trace/events/vsock_virtio_transport_common.h:39
 __traceiter_virtio_transport_alloc_pkt+0xc1/0x120 include/trace/events/vsock_virtio_transport_common.h:39
 __do_trace_virtio_transport_alloc_pkt include/trace/events/vsock_virtio_transport_common.h:39 [inline]
 trace_virtio_transport_alloc_pkt include/trace/events/vsock_virtio_transport_common.h:39 [inline]
 virtio_transport_alloc_skb+0x1108/0x1180 net/vmw_vsock/virtio_transport_common.c:312
 virtio_transport_send_pkt_info+0x570/0xff0 net/vmw_vsock/virtio_transport_common.c:391
 virtio_transport_connect+0xf5/0x150 net/vmw_vsock/virtio_transport_common.c:1080
 vsock_connect+0xaf5/0xd60 net/vmw_vsock/af_vsock.c:1716
 __sys_connect_file net/socket.c:2089 [inline]
 __sys_connect+0x312/0x450 net/socket.c:2108
 __do_sys_connect net/socket.c:2114 [inline]
 __se_sys_connect net/socket.c:2111 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2111
 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: 0033:0x7fd65079c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd52be1438 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fd650a15fa0 RCX: 00007fd65079c799
RDX: 0000000000000010 RSI: 0000200000000080 RDI: 0000000000000003
RBP: 00007fd650832bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd650a15fac R14: 00007fd650a15fa0 R15: 00007fd650a15fa0
 </TASK>

Allocated by task 5664:
 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 5576:
 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+0x76/0xd0 kernel/softirq.c:523
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x1aa/0x7d0 net/core/skbuff.c:697
 alloc_skb include/linux/skbuff.h:1383 [inline]
 mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886
 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025
 mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2268
 mld_dad_work+0x45/0x5b0 net/ipv6/mcast.c:2294
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

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 ffff888039269600
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 24 bytes inside of
 freed 192-byte region [ffff888039269600, ffff8880392696c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888039269a00 pfn:0x39269
flags: 0x4fff00000000200(workingset|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000200 ffff88801ac413c0 ffffea0001646350 ffffea00015fe190
raw: ffff888039269a00 000000000010000b 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 5643, tgid 5643 (syz.5.37), ts 117716289519, free_ts 117714764185
 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 15 tgid 15 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
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291
 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
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1063
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888039269500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888039269580: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888039269600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888039269680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888039269700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/27 23:36 upstream a75cb869a8cc 2cf092b8 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bpf_trace_run9
2026/02/27 21:40 upstream a75cb869a8cc 2cf092b8 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bpf_trace_run9
2026/02/27 20:35 upstream a75cb869a8cc 2cf092b8 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bpf_trace_run9
2026/02/27 19:35 upstream a75cb869a8cc 2cf092b8 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bpf_trace_run9
2026/02/27 22:35 upstream a75cb869a8cc 2cf092b8 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bpf_trace_run9
2026/02/27 18:20 upstream a75cb869a8cc 2cf092b8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bpf_trace_run9
* Struck through repros no longer work on HEAD.