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

Status: upstream: reported C repro on 2026/09/16 06:37
Reported-by: syzbot+d24bc1c42b24fc5b9447@syzkaller.appspotmail.com
First crash: 14d, last: 2h37m
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in __dynamic_pr_debug prio:high net nfc 17 syz, C 436 1h01m 42d 21/29 upstream: reported C repro on 2026/08/19 05:22
linux-6.6 KASAN: slab-out-of-bounds Read in __dynamic_pr_debug 17 11 1d07h 14d 0/2 upstream: reported on 2026/09/16 06:54
linux-6.1 KASAN: slab-out-of-bounds Read in __dynamic_pr_debug 17 syz, C 14 16h19m 12d 0/3 upstream: reported C repro on 2026/09/18 02:35

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in string_nocheck lib/vsprintf.c:642 [inline]
BUG: KASAN: slab-out-of-bounds in string+0x204/0x290 lib/vsprintf.c:724
Read of size 1 at addr ffff88814a744ca1 by task syz.0.17/4316

CPU: 1 PID: 4316 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 string_nocheck lib/vsprintf.c:642 [inline]
 string+0x204/0x290 lib/vsprintf.c:724
 vsnprintf+0x10db/0x1c20 lib/vsprintf.c:2811
 va_format lib/vsprintf.c:1713 [inline]
 pointer+0x7b2/0xc60 lib/vsprintf.c:2448
 vsnprintf+0xd7c/0x1c20 lib/vsprintf.c:2815
 vprintk_store+0x378/0x11b0 kernel/printk/printk.c:2164
 vprintk_emit+0x85/0x150 kernel/printk/printk.c:2258
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 __dynamic_pr_debug+0x196/0x240 lib/dynamic_debug.c:619
 nfc_llcp_wks_sap net/nfc/llcp_core.c:344 [inline]
 nfc_llcp_get_sdp_ssap+0x3c1/0x3f0 net/nfc/llcp_core.c:420
 llcp_sock_bind+0x3a2/0x770 net/nfc/llcp_sock.c:117
 __sys_bind+0x2e9/0x3e0 net/socket.c:1730
 __do_sys_bind net/socket.c:1741 [inline]
 __se_sys_bind net/socket.c:1739 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1739
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7efec8138159
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:00007fff34d35a68 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00007efec83bffa0 RCX: 00007efec8138159
RDX: 0000000000000060 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007efec81cf06b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efec83bffac R14: 00007efec83bffa0 R15: 00007efec83bffa0
 </TASK>

Allocated by task 4316:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522
 kmemdup+0x22/0x50 mm/util.c:128
 llcp_sock_bind+0x360/0x770 net/nfc/llcp_sock.c:107
 __sys_bind+0x2e9/0x3e0 net/socket.c:1730
 __do_sys_bind net/socket.c:1741 [inline]
 __se_sys_bind net/socket.c:1739 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1739
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88814a744c80
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 33 bytes inside of
 64-byte region [ffff88814a744c80, ffff88814a744cc0)
The buggy address belongs to the page:
page:ffffea000529d100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14a744
flags: 0x57ff00000000200(slab|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000200 ffffea00052ba740 0000001700000017 ffff888016c41640
raw: 0000000000000000 0000000080200020 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 19270739362, free_ts 0
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 __kmalloc+0x11d/0x340 mm/slub.c:4408
 kmalloc include/linux/slab.h:612 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 handler_new_ref+0x1fb/0x8d0 drivers/media/v4l2-core/v4l2-ctrls-core.c:1123
 v4l2_ctrl_add_handler+0x197/0x280 drivers/media/v4l2-core/v4l2-ctrls-core.c:1590
 vivid_create_controls+0x2ad8/0x3380 drivers/media/test-drivers/vivid/vivid-ctrls.c:1947
 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1860 [inline]
 vivid_probe+0x39ff/0x6240 drivers/media/test-drivers/vivid/vivid-core.c:2031
 platform_probe+0x137/0x1c0 drivers/base/platform.c:1391
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x276/0xc70 drivers/base/dd.c:595
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:805
 __driver_attach+0x45d/0x660 drivers/base/dd.c:1184
 bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88814a744b80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88814a744c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88814a744c80: 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff88814a744d00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
 ffff88814a744d80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================

Crashes (35):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/21 08:24 linux-5.15.y 0248c33e835e 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/30 09:38 linux-5.15.y 0248c33e835e 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/30 09:33 linux-5.15.y 0248c33e835e 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/29 07:23 linux-5.15.y 0248c33e835e 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/29 07:23 linux-5.15.y 0248c33e835e 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/29 04:15 linux-5.15.y 0248c33e835e 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/29 04:14 linux-5.15.y 0248c33e835e 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/28 22:07 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/28 17:43 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/28 15:21 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/25 20:44 linux-5.15.y 0248c33e835e f281d9d2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/23 01:07 linux-5.15.y 0248c33e835e 5207b90e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/22 22:58 linux-5.15.y 0248c33e835e 5207b90e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/22 08:16 linux-5.15.y 0248c33e835e e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/22 08:16 linux-5.15.y 0248c33e835e e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/21 20:51 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/21 07:07 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/21 05:27 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/20 04:45 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/20 02:20 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/19 07:05 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/18 10:00 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 23:29 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 23:29 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 21:59 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 19:46 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 19:46 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 19:08 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 19:08 linux-5.15.y 0248c33e835e 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/17 03:21 linux-5.15.y 0248c33e835e 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/16 09:40 linux-5.15.y 0248c33e835e 12a0a44a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/16 08:51 linux-5.15.y 0248c33e835e 12a0a44a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/16 08:51 linux-5.15.y 0248c33e835e 12a0a44a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/16 06:36 linux-5.15.y 0248c33e835e 12a0a44a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
2026/09/16 06:36 linux-5.15.y 0248c33e835e 12a0a44a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __dynamic_pr_debug
* Struck through repros no longer work on HEAD.