[v5.15] KASAN: use-after-free Read in rc_dev_uevent
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syzbot
Aug 4, 2026, 3:34:43 PM (yesterday) Aug 4
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 6e2fd6534337 Linux 5.15.213
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=176b13b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=23b1d1906b47c04d9a6d
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d7b46606b13d/disk-6e2fd653.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/da120fdeb081/vmlinux-6e2fd653.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c2643457e3f/bzImage-6e2fd653.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+23b1d1...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:642 [inline]
BUG: KASAN: use-after-free in string+0x204/0x290 lib/vsprintf.c:724
Read of size 1 at addr ffff8880744ff728 by task udevd/3557
CPU: 0 PID: 3557 Comm: udevd 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
add_uevent_var+0x1cd/0x460 lib/kobject_uevent.c:680
rc_dev_uevent+0x15b/0x190 drivers/media/rc/rc-main.c:1630
dev_uevent+0x4d6/0x740 drivers/base/core.c:2361
uevent_show+0x1b1/0x320 drivers/base/core.c:2410
dev_attr_show+0x50/0xb0 drivers/base/core.c:2110
sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61
seq_read_iter+0x460/0xc50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2167 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x75e/0xd50 fs/read_write.c:485
ksys_read+0x153/0x260 fs/read_write.c:623
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: 0033:0x7f95a80c6407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffe6130ce00 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f95a7fd8880 RCX: 00007f95a80c6407
RDX: 0000000000001000 RSI: 000056408e6bca00 RDI: 000000000000000c
RBP: 00007f95a820eff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f95a820eea0 R14: 0000000000000000 R15: 000056408e69e070
</TASK>
Allocated by task 4186:
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
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
redrat3_dev_probe+0x3ef/0x23c0 drivers/media/rc/redrat3.c:1025
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Freed by task 4186:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
redrat3_delete drivers/media/rc/redrat3.c:466 [inline]
redrat3_dev_probe+0x1b69/0x23c0 drivers/media/rc/redrat3.c:1126
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
The buggy address belongs to the object at ffff8880744ff000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1832 bytes inside of
2048-byte region [ffff8880744ff000, ffff8880744ff800)
The buggy address belongs to the page:
page:ffffea0001d13e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x744f8
head:ffffea0001d13e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 0000000100000001 ffff888016c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
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 4185, ts 65797054102, free_ts 65143510125
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_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_track_caller+0x11b/0x330 mm/slub.c:4930
kmemdup+0x22/0x50 mm/util.c:128
neigh_sysctl_register+0xab/0xa90 net/core/neighbour.c:3652
devinet_sysctl_register+0xa8/0x1f0 net/ipv4/devinet.c:2640
inetdev_init+0x28c/0x4d0 net/ipv4/devinet.c:277
inetdev_event+0x26f/0x1350 net/ipv4/devinet.c:1543
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
call_netdevice_notifiers net/core/dev.c:2088 [inline]
register_netdevice+0x12a8/0x1720 net/core/dev.c:10454
__rtnl_newlink net/core/rtnetlink.c:3540 [inline]
rtnl_newlink+0x14fe/0x1920 net/core/rtnetlink.c:3586
rtnetlink_rcv_msg+0x7f1/0xf10 net/core/rtnetlink.c:5698
netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
put_page include/linux/mm.h:1258 [inline]
__skb_frag_unref include/linux/skbuff.h:3254 [inline]
skb_release_data+0x35c/0x830 net/core/skbuff.c:672
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb+0x4c/0x60 net/core/skbuff.c:756
sk_eat_skb include/net/sock.h:2793 [inline]
tcp_recvmsg_locked+0x143d/0x2690 net/ipv4/tcp.c:2520
tcp_recvmsg+0x22a/0x760 net/ipv4/tcp.c:2566
inet_recvmsg+0x146/0x200 net/ipv4/af_inet.c:868
sock_recvmsg_nosec net/socket.c:969 [inline]
sock_recvmsg net/socket.c:987 [inline]
sock_read_iter+0x2c2/0x380 net/socket.c:1068
call_read_iter include/linux/fs.h:2167 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x75e/0xd50 fs/read_write.c:485
ksys_read+0x153/0x260 fs/read_write.c:623
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
Memory state around the buggy address:
ffff8880744ff600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880744ff680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880744ff700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880744ff780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880744ff800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 6e2fd6534337 Linux 5.15.213
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=176b13b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=23b1d1906b47c04d9a6d
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d7b46606b13d/disk-6e2fd653.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/da120fdeb081/vmlinux-6e2fd653.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c2643457e3f/bzImage-6e2fd653.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+23b1d1...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:642 [inline]
BUG: KASAN: use-after-free in string+0x204/0x290 lib/vsprintf.c:724
Read of size 1 at addr ffff8880744ff728 by task udevd/3557
CPU: 0 PID: 3557 Comm: udevd 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
add_uevent_var+0x1cd/0x460 lib/kobject_uevent.c:680
rc_dev_uevent+0x15b/0x190 drivers/media/rc/rc-main.c:1630
dev_uevent+0x4d6/0x740 drivers/base/core.c:2361
uevent_show+0x1b1/0x320 drivers/base/core.c:2410
dev_attr_show+0x50/0xb0 drivers/base/core.c:2110
sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61
seq_read_iter+0x460/0xc50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2167 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x75e/0xd50 fs/read_write.c:485
ksys_read+0x153/0x260 fs/read_write.c:623
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: 0033:0x7f95a80c6407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffe6130ce00 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f95a7fd8880 RCX: 00007f95a80c6407
RDX: 0000000000001000 RSI: 000056408e6bca00 RDI: 000000000000000c
RBP: 00007f95a820eff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f95a820eea0 R14: 0000000000000000 R15: 000056408e69e070
</TASK>
Allocated by task 4186:
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
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
redrat3_dev_probe+0x3ef/0x23c0 drivers/media/rc/redrat3.c:1025
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Freed by task 4186:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
redrat3_delete drivers/media/rc/redrat3.c:466 [inline]
redrat3_dev_probe+0x1b69/0x23c0 drivers/media/rc/redrat3.c:1126
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
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
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
The buggy address belongs to the object at ffff8880744ff000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1832 bytes inside of
2048-byte region [ffff8880744ff000, ffff8880744ff800)
The buggy address belongs to the page:
page:ffffea0001d13e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x744f8
head:ffffea0001d13e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 0000000100000001 ffff888016c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
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 4185, ts 65797054102, free_ts 65143510125
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_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_track_caller+0x11b/0x330 mm/slub.c:4930
kmemdup+0x22/0x50 mm/util.c:128
neigh_sysctl_register+0xab/0xa90 net/core/neighbour.c:3652
devinet_sysctl_register+0xa8/0x1f0 net/ipv4/devinet.c:2640
inetdev_init+0x28c/0x4d0 net/ipv4/devinet.c:277
inetdev_event+0x26f/0x1350 net/ipv4/devinet.c:1543
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
call_netdevice_notifiers net/core/dev.c:2088 [inline]
register_netdevice+0x12a8/0x1720 net/core/dev.c:10454
__rtnl_newlink net/core/rtnetlink.c:3540 [inline]
rtnl_newlink+0x14fe/0x1920 net/core/rtnetlink.c:3586
rtnetlink_rcv_msg+0x7f1/0xf10 net/core/rtnetlink.c:5698
netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
put_page include/linux/mm.h:1258 [inline]
__skb_frag_unref include/linux/skbuff.h:3254 [inline]
skb_release_data+0x35c/0x830 net/core/skbuff.c:672
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb+0x4c/0x60 net/core/skbuff.c:756
sk_eat_skb include/net/sock.h:2793 [inline]
tcp_recvmsg_locked+0x143d/0x2690 net/ipv4/tcp.c:2520
tcp_recvmsg+0x22a/0x760 net/ipv4/tcp.c:2566
inet_recvmsg+0x146/0x200 net/ipv4/af_inet.c:868
sock_recvmsg_nosec net/socket.c:969 [inline]
sock_recvmsg net/socket.c:987 [inline]
sock_read_iter+0x2c2/0x380 net/socket.c:1068
call_read_iter include/linux/fs.h:2167 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x75e/0xd50 fs/read_write.c:485
ksys_read+0x153/0x260 fs/read_write.c:623
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
Memory state around the buggy address:
ffff8880744ff600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880744ff680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880744ff700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880744ff780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880744ff800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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#syz undup
syzbot
Aug 4, 2026, 9:50:40 PM (20 hours ago) Aug 4
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: fb28aa725e05 Linux 6.1.180
syzbot found the following issue on:
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11fe93b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=f4394e2e2707033572a8
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KASAN: use-after-free in string+0x204/0x290 lib/vsprintf.c:725
Read of size 1 at addr ffff888072842728 by task udevd/3638
CPU: 1 PID: 3638 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
Call Trace:
<TASK>
print_address_description mm/kasan/report.c:316 [inline]
print_report+0xa8/0x210 mm/kasan/report.c:420
kasan_report+0x10b/0x140 mm/kasan/report.c:524
string_nocheck lib/vsprintf.c:643 [inline]
string+0x204/0x290 lib/vsprintf.c:725
vsnprintf+0x10db/0x1c20 lib/vsprintf.c:2805
add_uevent_var+0x1cd/0x460 lib/kobject_uevent.c:680
rc_dev_uevent+0x15b/0x190 drivers/media/rc/rc-main.c:1631
dev_uevent+0x4d6/0x740 drivers/base/core.c:2622
uevent_show+0x1a8/0x320 drivers/base/core.c:2671
dev_attr_show+0x50/0xb0 drivers/base/core.c:2372
sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59
seq_read_iter+0x460/0xc50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x471/0x960 fs/read_write.c:470
ksys_read+0x14d/0x260 fs/read_write.c:613
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: 0033:0x7f054f6a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffe8b708a80 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f054fd9f880 RCX: 00007f054f6a7407
RDX: 0000000000001000 RSI: 000055c3efa3e340 RDI: 000000000000000c
RBP: 00007f054f7efff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f054f7efea0 R14: 0000000000000000 R15: 000055c3efa1f7a0
</TASK>
Allocated by task 4832:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
redrat3_dev_probe+0x3ef/0x23c0 drivers/media/rc/redrat3.c:1025
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:1034
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3712
usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:1034
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3712
usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2659
hub_port_connect drivers/usb/core/hub.c:5517 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
port_event drivers/usb/core/hub.c:5817 [inline]
hub_event+0x2b2f/0x5200 drivers/usb/core/hub.c:5899
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Freed by task 4832:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xb6/0x200 mm/slub.c:3700
redrat3_delete drivers/media/rc/redrat3.c:466 [inline]
redrat3_dev_probe+0x1b69/0x23c0 drivers/media/rc/redrat3.c:1126
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
redrat3_dev_probe+0x1b69/0x23c0 drivers/media/rc/redrat3.c:1126
usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:1034
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3712
usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:1034
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3712
usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2659
hub_port_connect drivers/usb/core/hub.c:5517 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
port_event drivers/usb/core/hub.c:5817 [inline]
hub_event+0x2b2f/0x5200 drivers/usb/core/hub.c:5899
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
The buggy address belongs to the object at ffff888072842000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1832 bytes inside of
2048-byte region [ffff888072842000, ffff888072842800)
The buggy address is located 1832 bytes inside of
The buggy address belongs to the physical page:
page:ffffea0001ca1000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x72840
head:ffffea0001ca1000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888017442000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4834, tgid 4834 (kworker/0:18), ts 154548884117, free_ts 154484553553
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
prep_new_page mm/page_alloc.c:2567 [inline]
get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
alloc_slab_page+0x5d/0x180 mm/slub.c:1799
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x87/0x2d0 mm/slub.c:1997
___slab_alloc+0xbc5/0x1240 mm/slub.c:3154
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398
__do_kmalloc_node mm/slab_common.c:935 [inline]
__kmalloc_node_track_caller+0xa0/0x240 mm/slab_common.c:956
kmalloc_reserve net/core/skbuff.c:446 [inline]
__alloc_skb+0x226/0x7d0 net/core/skbuff.c:515
alloc_skb include/linux/skbuff.h:1303 [inline]
mld_newpack+0x12d/0xc10 net/ipv6/mcast.c:1773
add_grhead net/ipv6/mcast.c:1884 [inline]
add_grec+0x1466/0x19c0 net/ipv6/mcast.c:2023
mld_send_cr net/ipv6/mcast.c:2146 [inline]
mld_ifc_work+0x6eb/0xab0 net/ipv6/mcast.c:2690
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1487 [inline]
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pcp_prepare mm/page_alloc.c:1537 [inline]
free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509
free_slab mm/slub.c:2036 [inline]
discard_slab mm/slub.c:2042 [inline]
__unfreeze_partials+0x188/0x1e0 mm/slub.c:2591
put_cpu_partial+0x17c/0x250 mm/slub.c:2667
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
kmem_cache_alloc_node+0x1ad/0x310 mm/slub.c:3404
__alloc_skb+0xf9/0x7d0 net/core/skbuff.c:505
alloc_skb include/linux/skbuff.h:1303 [inline]
nlmsg_new include/net/netlink.h:998 [inline]
rtmsg_ifinfo_build_skb+0x80/0x190 net/core/rtnetlink.c:3980
rtmsg_ifinfo_event net/core/rtnetlink.c:4018 [inline]
rtnetlink_event+0xd1/0x1a0 net/core/rtnetlink.c:6217
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
call_netdevice_notifiers net/core/dev.c:2066 [inline]
dev_set_mac_address+0x2ed/0x400 net/core/dev.c:8937
bond_set_mac_address+0x2c4/0x820 drivers/net/bonding/bond_main.c:4851
dev_set_mac_address+0x27f/0x400 net/core/dev.c:8933
Memory state around the buggy address:
ffff888072842680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888072842700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888072842780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888072842800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
syzbot
1:56 PM (3 hours ago) 1:56 PM
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1560d3b9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117a0e49580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f4394e...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KASAN: use-after-free in string+0x204/0x290 lib/vsprintf.c:725
Read of size 1 at addr ffff8880765a9728 by task udevd/3639
CPU: 1 PID: 3639 Comm: udevd Not tainted syzkaller #0
RAX: ffffffffffffffda RBX: 00007fbdf753d880 RCX: 00007fbdf75c9407
RDX: 0000000000001000 RSI: 00005650eca436b0 RDI: 000000000000000c
RBP: 00007fbdf7711ff0 R08: 0000000000000000 R09: 0000000000000000
</TASK>
Allocated by task 41:
Freed by task 41:
The buggy address belongs to the object at ffff8880765a9000
The buggy address belongs to the physical page:
page:ffffea0001d96a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x765a8
head:ffffea0001d96a00 order:3 compound_mapcount:0 compound_pincount:0
__kmem_cache_alloc_lru mm/slub.c:3374 [inline]
kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383
getname_flags+0xb7/0x500 fs/namei.c:139
vfs_fstatat fs/stat.c:266 [inline]
__do_sys_newfstatat fs/stat.c:437 [inline]
__se_sys_newfstatat fs/stat.c:431 [inline]
__x64_sys_newfstatat+0x16f/0x240 fs/stat.c:431
ffff8880765a9680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880765a9700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880765a9780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880765a9800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=f4394e2e2707033572a8
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13192bb9580000
dashboard link: https://syzkaller.appspot.com/bug?extid=f4394e2e2707033572a8
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117a0e49580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f4394e...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KASAN: use-after-free in string+0x204/0x290 lib/vsprintf.c:725
CPU: 1 PID: 3639 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0xa8/0x210 mm/kasan/report.c:420
kasan_report+0x10b/0x140 mm/kasan/report.c:524
string_nocheck lib/vsprintf.c:643 [inline]
string+0x204/0x290 lib/vsprintf.c:725
vsnprintf+0x10db/0x1c20 lib/vsprintf.c:2805
add_uevent_var+0x1cd/0x460 lib/kobject_uevent.c:680
rc_dev_uevent+0x15b/0x190 drivers/media/rc/rc-main.c:1631
dev_uevent+0x4d6/0x740 drivers/base/core.c:2622
uevent_show+0x1a8/0x320 drivers/base/core.c:2671
dev_attr_show+0x50/0xb0 drivers/base/core.c:2372
sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59
seq_read_iter+0x460/0xc50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x471/0x960 fs/read_write.c:470
ksys_read+0x14d/0x260 fs/read_write.c:613
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: 0033:0x7fbdf75c9407
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0xa8/0x210 mm/kasan/report.c:420
kasan_report+0x10b/0x140 mm/kasan/report.c:524
string_nocheck lib/vsprintf.c:643 [inline]
string+0x204/0x290 lib/vsprintf.c:725
vsnprintf+0x10db/0x1c20 lib/vsprintf.c:2805
add_uevent_var+0x1cd/0x460 lib/kobject_uevent.c:680
rc_dev_uevent+0x15b/0x190 drivers/media/rc/rc-main.c:1631
dev_uevent+0x4d6/0x740 drivers/base/core.c:2622
uevent_show+0x1a8/0x320 drivers/base/core.c:2671
dev_attr_show+0x50/0xb0 drivers/base/core.c:2372
sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59
seq_read_iter+0x460/0xc50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x471/0x960 fs/read_write.c:470
ksys_read+0x14d/0x260 fs/read_write.c:613
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
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc5a106800 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fbdf753d880 RCX: 00007fbdf75c9407
RDX: 0000000000001000 RSI: 00005650eca436b0 RDI: 000000000000000c
RBP: 00007fbdf7711ff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007fbdf7711ea0 R14: 0000000000000000 R15: 00005650ec8875d0
</TASK>
Allocated by task 41:
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1832 bytes inside of
2048-byte region [ffff8880765a9000, ffff8880765a9800)
The buggy address is located 1832 bytes inside of
The buggy address belongs to the physical page:
head:ffffea0001d96a00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888017442000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 41, tgid 41 (kworker/1:1), ts 83989989245, free_ts 77325807102
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
prep_new_page mm/page_alloc.c:2567 [inline]
get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
alloc_slab_page+0x5d/0x180 mm/slub.c:1799
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x87/0x2d0 mm/slub.c:1997
___slab_alloc+0xbc5/0x1240 mm/slub.c:3154
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398
kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
prep_new_page mm/page_alloc.c:2567 [inline]
get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
alloc_slab_page+0x5d/0x180 mm/slub.c:1799
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x87/0x2d0 mm/slub.c:1997
___slab_alloc+0xbc5/0x1240 mm/slub.c:3154
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
usb_set_configuration+0x3b6/0x2030 drivers/usb/core/message.c:2051
kzalloc include/linux/slab.h:699 [inline]
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1487 [inline]
free_pcp_prepare mm/page_alloc.c:1537 [inline]
free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509
free_slab mm/slub.c:2036 [inline]
discard_slab mm/slub.c:2042 [inline]
__unfreeze_partials+0x188/0x1e0 mm/slub.c:2591
put_cpu_partial+0x17c/0x250 mm/slub.c:2667
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
slab_alloc mm/slub.c:3367 [inline]
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1487 [inline]
free_pcp_prepare mm/page_alloc.c:1537 [inline]
free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509
free_slab mm/slub.c:2036 [inline]
discard_slab mm/slub.c:2042 [inline]
__unfreeze_partials+0x188/0x1e0 mm/slub.c:2591
put_cpu_partial+0x17c/0x250 mm/slub.c:2667
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
__kmem_cache_alloc_lru mm/slub.c:3374 [inline]
kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383
getname_flags+0xb7/0x500 fs/namei.c:139
vfs_fstatat fs/stat.c:266 [inline]
__do_sys_newfstatat fs/stat.c:437 [inline]
__se_sys_newfstatat fs/stat.c:431 [inline]
__x64_sys_newfstatat+0x16f/0x240 fs/stat.c:431
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
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Memory state around the buggy address:
ffff8880765a9600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880765a9680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880765a9700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880765a9780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880765a9800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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