Hello,
syzbot found the following crash on:
HEAD commit: e0bd8d79 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=12f037c9600000
kernel config: https://syzkaller.appspot.com/x/.config?x=8847e5384a16f66a
dashboard link: https://syzkaller.appspot.com/bug?extid=d8c25680ec62d91f78fe
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d8c25680ec62d91f78fe@xxxxxxxxxxxxxxxxxxxxxxxxx
usb 6-1: usbvision_write_reg: failed: error -2
usbvision_audio_off: can't write reg
usbvision_radio_close: Final disconnect
==================================================================
BUG: KASAN: use-after-free in sysfs_remove_file_ns+0x5f/0x70
fs/sysfs/file.c:467
Read of size 8 at addr ffff8881d42b03c0 by task v4l_id/7021
CPU: 1 PID: 7021 Comm: v4l_id Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:618
sysfs_remove_file_ns+0x5f/0x70 fs/sysfs/file.c:467
sysfs_remove_file include/linux/sysfs.h:536 [inline]
device_remove_file+0x25/0x30 drivers/base/core.c:1611
usbvision_remove_sysfs drivers/media/usb/usbvision/usbvision-video.c:288
[inline]
usbvision_release+0x97/0x1c0
drivers/media/usb/usbvision/usbvision-video.c:1339
usbvision_radio_close.cold+0x6f/0x74
drivers/media/usb/usbvision/usbvision-video.c:1113
v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
__fput+0x2d7/0x840 fs/file_table.c:280
task_work_run+0x13f/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:300
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f0392c7d2b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007fff61410398 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f0392c7d2b0
RDX: 00007f0392f33df0 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f0392f33df0 R09: 000000000000000a
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007fff614104f0 R14: 0000000000000000 R15: 0000000000000000
Allocated by task 101:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:493 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:466
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:748 [inline]
usbvision_alloc drivers/media/usb/usbvision/usbvision-video.c:1298 [inline]
usbvision_probe.cold+0x5c5/0x1f1f
drivers/media/usb/usbvision/usbvision-video.c:1452
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0xae6/0x16f0 drivers/base/core.c:2201
usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0xae6/0x16f0 drivers/base/core.c:2201
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Freed by task 2734:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:455
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1474 [inline]
slab_free mm/slub.c:3016 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3957
usbvision_release+0x181/0x1c0
drivers/media/usb/usbvision/usbvision-video.c:1347
usbvision_disconnect+0x16c/0x1d0
drivers/media/usb/usbvision/usbvision-video.c:1570
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x420/0xb10 drivers/base/core.c:2375
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
The buggy address belongs to the object at ffff8881d42b0000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 960 bytes inside of
8192-byte region [ffff8881d42b0000, ffff8881d42b2000)
The buggy address belongs to the page:
page:ffffea000750ac00 refcount:1 mapcount:0 mapping:ffff8881da00c500
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 0000000000000000 0000000100000001 ffff8881da00c500
raw: 0000000000000000 0000000080030003 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881d42b0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d42b0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d42b0380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d42b0400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d42b0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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