KASAN: slab-out-of-bounds Read in sk_skb_adjust_room

Status: upstream: reported C repro on 2026/10/04 16:38
Reported-by: syzbot+8ea4656e51f5b886f47c@syzkaller.appspotmail.com
First crash: 3d18h, last: 18h37m
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room 17 syz, C 10 17h18m 3d14h 0/3 upstream: reported C repro on 2026/10/04 20:39
android-5-15 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room 17 syz, C 6 1d03h 3d10h 0/2 upstream: reported C repro on 2026/10/05 01:06
android-6-1 KASAN: use-after-free Read in sk_skb_adjust_room 19 syz, C 16 1d02h 3d09h 0/2 upstream: reported C repro on 2026/10/05 01:18

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in tls_get_ctx include/net/tls.h:385 [inline]
BUG: KASAN: slab-out-of-bounds in tls_sw_has_ctx_rx include/net/tls.h:417 [inline]
BUG: KASAN: slab-out-of-bounds in ____sk_skb_adjust_room net/core/filter.c:3688 [inline]
BUG: KASAN: slab-out-of-bounds in sk_skb_adjust_room+0x2b0/0x52c net/core/filter.c:3665
Read of size 8 at addr ffff0000d3534f90 by task syz.0.17/4468

CPU: 1 PID: 4468 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
 tls_get_ctx include/net/tls.h:385 [inline]
 tls_sw_has_ctx_rx include/net/tls.h:417 [inline]
 ____sk_skb_adjust_room net/core/filter.c:3688 [inline]
 sk_skb_adjust_room+0x2b0/0x52c net/core/filter.c:3665
 bpf_prog_e15ab8bd9cea3c06+0x58/0x90
 bpf_dispatcher_nop_func include/linux/bpf.h:1013 [inline]
 __bpf_prog_run include/linux/filter.h:608 [inline]
 bpf_prog_run include/linux/filter.h:615 [inline]
 bpf_prog_run_pin_on_cpu+0x70/0x1e8 include/linux/filter.h:632
 sk_psock_verdict_recv+0x23c/0x86c net/core/skmsg.c:1256
 unix_stream_read_skb+0x11c/0x270 net/unix/af_unix.c:2774
 sk_psock_verdict_data_ready+0x94/0x348 net/core/skmsg.c:1274
 unix_stream_sendmsg+0x4d4/0x894 net/unix/af_unix.c:2258
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x324/0x440 net/socket.c:2153
 __do_sys_sendto net/socket.c:2165 [inline]
 __se_sys_sendto net/socket.c:2161 [inline]
 __arm64_sys_sendto+0xe4/0x104 net/socket.c:2161
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4468:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x430 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x234/0x310 mm/slub.c:3383
 sk_prot_alloc+0x60/0x1e8 net/core/sock.c:2050
 sk_alloc+0x44/0x3a0 net/core/sock.c:2112
 unix_create1+0xd0/0x750 net/unix/af_unix.c:-1
 unix_create+0x148/0x1f4 net/unix/af_unix.c:1017
 __sock_create+0x448/0x8a8 net/socket.c:1550
 sock_create net/socket.c:1606 [inline]
 __sys_socketpair+0x35c/0x6d8 net/socket.c:1737
 __do_sys_socketpair net/socket.c:1786 [inline]
 __se_sys_socketpair net/socket.c:1783 [inline]
 __arm64_sys_socketpair+0xa0/0xbc net/socket.c:1783
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000d3534800
 which belongs to the cache UNIX-STREAM of size 1920
The buggy address is located 16 bytes to the right of
 1920-byte region [ffff0000d3534800, ffff0000d3534f80)

The buggy address belongs to the physical page:
page:00000000393cbda9 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113530
head:00000000393cbda9 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff0000dce78801
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000122 ffff0000c4f28300
raw: 0000000000000000 0000000080100010 00000001ffffffff ffff0000dce78801
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d3534e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000d3534f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000d3534f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff0000d3535000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d3535080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/04 17:49 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/04 17:11 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/07 16:40 linux-6.1.y a500ba24937a 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/07 16:40 linux-6.1.y a500ba24937a 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/07 09:16 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/07 09:15 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/05 19:42 linux-6.1.y a500ba24937a af63e995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/05 19:42 linux-6.1.y a500ba24937a af63e995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/05 00:48 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/05 00:44 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/07 08:09 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/07 08:08 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/05 02:12 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/05 02:12 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/04 16:48 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
2026/10/04 16:38 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in sk_skb_adjust_room
* Struck through repros no longer work on HEAD.