syzbot


KASAN: slab-out-of-bounds Write in __bpf_get_stackid

Status: upstream: reported C repro on 2026/02/05 00:19
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+6d2cdc0a08307ab5cc60@syzkaller.appspotmail.com
First crash: 5d11h, last: 48m
Bug presence (2)
Date Name Commit Repro Result
2026/02/05 lts (merge base) e50b81c50fcb C [report] KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/05 upstream (ToT) f14faaf3a1fb C Didn't crash
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: slab-out-of-bounds Write in __bpf_get_stackid origin:lts-only 21 C error 11 1d09h 182d 0/2 upstream: reported C repro on 2025/08/11 20:18
linux-6.1 KASAN: slab-out-of-bounds Write in __bpf_get_stackid 21 C 3 1d09h 2d05h 0/3 upstream: reported C repro on 2026/02/08 05:29
upstream KASAN: slab-out-of-bounds Write in __bpf_get_stackid bpf 21 C error 170 101d 196d 29/29 fixed on 2026/01/07 12:29

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in __bpf_get_stackid+0x6fa/0x960 kernel/bpf/stackmap.c:274
Write of size 56 at addr ffff888110372690 by task syz.2.17/375

CPU: 1 PID: 375 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <IRQ>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 memcpy+0x44/0x70 mm/kasan/shadow.c:66
 __bpf_get_stackid+0x6fa/0x960 kernel/bpf/stackmap.c:274
 ____bpf_get_stackid_pe kernel/bpf/stackmap.c:365 [inline]
 bpf_get_stackid_pe+0x2ee/0x400 kernel/bpf/stackmap.c:334
 bpf_prog_fa73c8c086b491e8+0x21/0x31
 bpf_dispatcher_nop_func include/linux/bpf.h:987 [inline]
 __bpf_prog_run include/linux/filter.h:607 [inline]
 bpf_prog_run include/linux/filter.h:614 [inline]
 bpf_overflow_handler+0x3d0/0x5e0 kernel/events/core.c:10238
 __perf_event_overflow+0x437/0x620 kernel/events/core.c:9448
 perf_swevent_hrtimer+0x400/0x5b0 kernel/events/core.c:10879
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x3d5/0xa00 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3c7/0x8c0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x11e/0x440 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:_perf_ioctl kernel/events/core.c:5778 [inline]
RIP: 0010:perf_ioctl+0x147a/0x1e70 kernel/events/core.c:5837
Code: 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 40 02 00 00 0f 85 3e 09 00 00 4c 89 f8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <e8> 41 6a d7 ff 45 31 ff e9 6e ff ff ff e8 34 6a d7 ff 41 bf ea ff
RSP: 0018:ffffc90000a67be0 EFLAGS: 00010246
RAX: ffffffff8199f62d RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88811362bcc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000a67e80 R08: ffff888114a0c007 R09: 1ffff11022941800
R10: dffffc0000000000 R11: ffffed1022941801 R12: 0000000040042408
R13: dffffc0000000000 R14: fffff5200014cf8c R15: ffffc900007e5000
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7faf49f9aeb9
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:00007ffff5c41af8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007faf4a215fa0 RCX: 00007faf49f9aeb9
RDX: 0000000000000004 RSI: 0000000040042408 RDI: 0000000000000005
RBP: 00007faf4a008c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faf4a215fac R14: 00007faf4a215fa0 R15: 00007faf4a215fa0
 </TASK>

Allocated by task 375:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc_node+0xb2/0x1e0 mm/slab_common.c:945
 kmalloc_node include/linux/slab.h:589 [inline]
 __bpf_map_area_alloc kernel/bpf/syscall.c:328 [inline]
 bpf_map_area_alloc+0x4b/0xe0 kernel/bpf/syscall.c:341
 prealloc_elems_and_freelist+0x8a/0x1e0 kernel/bpf/stackmap.c:51
 stack_map_alloc+0x3a7/0x530 kernel/bpf/stackmap.c:117
 find_and_alloc_map kernel/bpf/syscall.c:133 [inline]
 map_create+0x49c/0xd80 kernel/bpf/syscall.c:1126
 __sys_bpf+0x34e/0x850 kernel/bpf/syscall.c:4987
 __do_sys_bpf kernel/bpf/syscall.c:5109 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5107 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5107
 x64_sys_call+0x488/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888110372680
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 16 bytes inside of
 64-byte region [ffff888110372680, ffff8881103726c0)

The buggy address belongs to the physical page:
page:ffffea000440dc80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110372
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000122 ffff888100042780
raw: 0000000000000000 0000000000200020 00000001ffffffff 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 364, tgid 364 (syz-executor), ts 31188271111, free_ts 31092581716
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4554
 __alloc_pages+0x1d9/0x480 mm/page_alloc.c:5868
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3d0 mm/slub.c:2020
 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x203/0x2c0 mm/slub.c:3423
 kmalloc_trace+0x29/0xb0 mm/slab_common.c:1028
 kmalloc include/linux/slab.h:563 [inline]
 call_modprobe kernel/kmod.c:79 [inline]
 __request_module+0x2a7/0x910 kernel/kmod.c:170
 dev_load+0x5b/0xb0 net/core/dev_ioctl.c:449
 dev_ioctl+0x3c6/0xd10 net/core/dev_ioctl.c:514
 sock_do_ioctl+0x252/0x330 net/socket.c:1208
 sock_ioctl+0x4ca/0x720 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1551 [inline]
 free_pcp_prepare mm/page_alloc.c:1625 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589
 free_unref_page+0x95/0x540 mm/page_alloc.c:3687
 free_the_page mm/page_alloc.c:836 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:5957
 __free_slab+0xca/0x1a0 mm/slub.c:2044
 free_slab mm/slub.c:2059 [inline]
 discard_slab mm/slub.c:2065 [inline]
 __unfreeze_partials+0x160/0x190 mm/slub.c:2614
 put_cpu_partial+0xa9/0x100 mm/slub.c:2690
 __slab_free+0x1c4/0x280 mm/slub.c:3589
 do_slab_free mm/slub.c:3666 [inline]
 ___cache_free+0xbf/0xd0 mm/slub.c:3722
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311
 kasan_slab_alloc include/linux/kasan.h:202 [inline]
 slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3382 [inline]
 __kmem_cache_alloc_node+0x192/0x2c0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc_node+0xa1/0x1e0 mm/slab_common.c:945
 kmalloc_node include/linux/slab.h:589 [inline]
 kvmalloc_node+0x28a/0x460 mm/util.c:592
 kvmalloc include/linux/slab.h:716 [inline]
 kvzalloc include/linux/slab.h:724 [inline]
 bucket_table_alloc lib/rhashtable.c:184 [inline]
 rhashtable_rehash_alloc lib/rhashtable.c:360 [inline]
 rht_deferred_worker+0x2e8/0x14e0 lib/rhashtable.c:420

Memory state around the buggy address:
 ffff888110372580: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888110372600: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888110372680: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
                                  ^
 ffff888110372700: 00 00 00 00 00 00 00 03 fc fc fc fc fc fc fc fc
 ffff888110372780: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
   0:	00 65 48             	add    %ah,0x48(%rbp)
   3:	8b 04 25 28 00 00 00 	mov    0x28,%eax
   a:	48 3b 84 24 40 02 00 	cmp    0x240(%rsp),%rax
  11:	00
  12:	0f 85 3e 09 00 00    	jne    0x956
  18:	4c 89 f8             	mov    %r15,%rax
  1b:	48 8d 65 d8          	lea    -0x28(%rbp),%rsp
  1f:	5b                   	pop    %rbx
  20:	41 5c                	pop    %r12
  22:	41 5d                	pop    %r13
  24:	41 5e                	pop    %r14
  26:	41 5f                	pop    %r15
  28:	5d                   	pop    %rbp
  29:	c3                   	ret
* 2a:	e8 41 6a d7 ff       	call   0xffd76a70 <-- trapping instruction
  2f:	45 31 ff             	xor    %r15d,%r15d
  32:	e9 6e ff ff ff       	jmp    0xffffffa5
  37:	e8 34 6a d7 ff       	call   0xffd76a70
  3c:	41                   	rex.B
  3d:	bf                   	.byte 0xbf
  3e:	ea                   	(bad)
  3f:	ff                   	.byte 0xff

Crashes (27):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/08 03:47 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/05 01:30 android14-6.1 775f23d50ca8 ea10c935 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/05 00:50 android14-6.1 775f23d50ca8 ea10c935 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/05 00:08 android14-6.1 775f23d50ca8 ea10c935 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/10 09:53 android14-6.1 c9e2710a7bd0 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/10 07:47 android14-6.1 c9e2710a7bd0 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/10 04:13 android14-6.1 c9e2710a7bd0 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 17:02 android14-6.1 c9e2710a7bd0 df949cd9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 10:09 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 05:00 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 04:24 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 03:37 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 01:51 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 01:51 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 01:51 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/09 01:14 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/08 20:55 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/08 17:23 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/08 11:48 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/08 10:06 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/08 02:25 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/08 01:13 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/07 22:07 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/07 21:36 android14-6.1 c9e2710a7bd0 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/07 14:02 android14-6.1 c9e2710a7bd0 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/07 06:08 android14-6.1 c9e2710a7bd0 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
2026/02/04 23:25 android14-6.1 775f23d50ca8 ea10c935 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: slab-out-of-bounds Write in __bpf_get_stackid
* Struck through repros no longer work on HEAD.