==================================================================
BUG: KASAN: slab-out-of-bounds in strnchr+0x5e/0x80 lib/string.c:405
Read of size 1 at addr ffff88802873b3b0 by task swapper/0/0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
strnchr+0x5e/0x80 lib/string.c:405
bpf_bprintf_prepare+0x167/0x13d0 kernel/bpf/helpers.c:829
____bpf_snprintf kernel/bpf/helpers.c:1065 [inline]
bpf_snprintf+0xd3/0x1b0 kernel/bpf/helpers.c:1049
bpf_prog_c2925c0a7ac12d80+0x58/0x60
bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
__bpf_prog_run include/linux/filter.h:723 [inline]
bpf_prog_run include/linux/filter.h:730 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run1+0x27f/0x4c0 kernel/trace/bpf_trace.c:2115
__bpf_trace_rcu_utilization+0xa1/0xf0 include/trace/events/rcu.h:27
__do_trace_rcu_utilization include/trace/events/rcu.h:27 [inline]
trace_rcu_utilization+0x191/0x1c0 include/trace/events/rcu.h:27
rcu_core+0x130/0x1870 kernel/rcu/tree.c:2830
handle_softirqs+0x27d/0x850 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 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
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 50 0c 00 f3 0f 1e fa fb f4 c8 ed 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: f552fd969d6f2500 RBX: ffffffff81978fba RCX: f552fd969d6f2500
RDX: 0000000000000001 RSI: ffffffff8d792d97 RDI: ffffffff8bc086e0
RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f822370
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3a7/0x400 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
Allocated by task 6003:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
kasan_kmalloc include/linux/kasan.h:262 [inline]
__do_kmalloc_node mm/slub.c:5657 [inline]
__kmalloc_node_noprof+0x57a/0x820 mm/slub.c:5663
kmalloc_node_noprof include/linux/slab.h:987 [inline]
__bpf_map_area_alloc kernel/bpf/syscall.c:395 [inline]
bpf_map_area_alloc+0x64/0x180 kernel/bpf/syscall.c:408
insn_array_alloc+0x52/0x140 kernel/bpf/bpf_insn_array.c:49
map_create+0xafd/0x16a0 kernel/bpf/syscall.c:1514
__sys_bpf+0x682/0x8a0 kernel/bpf/syscall.c:6189
__do_sys_bpf kernel/bpf/syscall.c:6320 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6318 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6318
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88802873b000
which belongs to the cache kmalloc-cg-1k of size 1024
The buggy address is located 0 bytes to the right of
allocated 944-byte region [ffff88802873b000, ffff88802873b3b0)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28738
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880761bbc01
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffb0280 ffffea0000a76e00 dead000000000003
raw: 0000000000000000 0000000080100010 00000000f5000000 ffff8880761bbc01
head: 00fff00000000040 ffff88813ffb0280 ffffea0000a76e00 dead000000000003
head: 0000000000000000 0000000080100010 00000000f5000000 ffff8880761bbc01
head: 00fff00000000003 ffffea0000a1ce01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
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 5496, tgid 5496 (dhcpcd), ts 57027219415, free_ts 56926940909
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
prep_new_page mm/page_alloc.c:1854 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3b0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xf2b/0x1960 mm/slub.c:4656
__slab_alloc+0x65/0x100 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_node_track_caller_noprof+0x5d4/0x820 mm/slub.c:5764
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
__alloc_skb+0x27e/0x430 net/core/skbuff.c:690
alloc_skb include/linux/skbuff.h:1383 [inline]
alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6712
sock_alloc_send_pskb+0x84d/0x980 net/core/sock.c:2995
unix_dgram_sendmsg+0x454/0x1840 net/unix/af_unix.c:2130
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
sock_write_iter+0x279/0x360 net/socket.c:1195
do_iter_readv_writev+0x623/0x8c0 fs/read_write.c:-1
page last free pid 5662 tgid 5662 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
__free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x146/0x170 mm/slub.c:3886
put_cpu_partial+0x1f2/0x2d0 mm/slub.c:3961
__slab_free+0x288/0x2a0 mm/slub.c:5952
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
proc_reg_open+0x1f4/0x540 fs/proc/inode.c:502
do_dentry_open+0x7ce/0x1420 fs/open.c:962
vfs_open+0x3b/0x340 fs/open.c:1094
do_open fs/namei.c:4628 [inline]
path_openat+0x340e/0x3dd0 fs/namei.c:4787
do_filp_open+0x1fa/0x410 fs/namei.c:4814
do_sys_openat2+0x121/0x200 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
Memory state around the buggy address:
ffff88802873b280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88802873b300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88802873b380: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
^
ffff88802873b400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802873b480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: cc int3
1: cc int3
2: cc int3
3: cc int3
4: cc int3
5: cc int3
6: cc int3
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: f3 0f 1e fa endbr64
1b: 66 90 xchg %ax,%ax
1d: 0f 00 2d 93 50 0c 00 verw 0xc5093(%rip) # 0xc50b7
24: f3 0f 1e fa endbr64
28: fb sti
29: f4 hlt
* 2a: e9 c8 ed 02 00 jmp 0x2edf7 <-- trapping instruction
2f: cc int3
30: cc int3
31: cc int3
32: cc int3
33: cc int3
34: cc int3
35: cc int3
36: cc int3
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop