[syzbot] KASAN: use-after-free Read in send_packet

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8288c99fc263 usb: misc: onboard_usb_hub: Remove duplicated..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=17a54e22080000
kernel config: https://syzkaller.appspot.com/x/.config?x=6749cc6053521b55
dashboard link: https://syzkaller.appspot.com/bug?extid=f1a69784f6efe748c3bf
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f1a697...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline]
BUG: KASAN: use-after-free in send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627
Read of size 4 at addr ffff888109b6b000 by task syz-executor.2/7852

CPU: 1 PID: 7852 Comm: syz-executor.2 Not tainted 5.19.0-rc7-syzkaller-00199-g8288c99fc263 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
print_report mm/kasan/report.c:429 [inline]
kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
__create_pipe include/linux/usb.h:1945 [inline]
send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627
vfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991
vfs_write+0x269/0xac0 fs/read_write.c:589
ksys_write+0x127/0x250 fs/read_write.c:644
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f218188a209
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2180fdf168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f218199d030 RCX: 00007f218188a209
RDX: 0000000000000001 RSI: 0000000020001000 RDI: 0000000000000004
RBP: 00007f21818e4161 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdf1861bff R14: 00007f2180fdf300 R15: 0000000000022000
</TASK>

Allocated by task 4094:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
__kasan_kmalloc+0x81/0xa0 mm/kasan/common.c:524
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
usb_alloc_dev+0x51/0xf00 drivers/usb/core/usb.c:582
hub_port_connect drivers/usb/core/hub.c:5255 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]
hub_event+0x2055/0x4690 drivers/usb/core/hub.c:5735
process_one_work+0x996/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2ef/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Freed by task 4215:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0x10f/0x190 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1754 [inline]
slab_free_freelist_hook mm/slub.c:1780 [inline]
slab_free mm/slub.c:3536 [inline]
kfree+0xc1/0x4f0 mm/slub.c:4584
device_release+0x9f/0x240 drivers/base/core.c:2241
kobject_cleanup lib/kobject.c:673 [inline]
kobject_release lib/kobject.c:704 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c8/0x540 lib/kobject.c:721
put_device+0x1b/0x30 drivers/base/core.c:3535
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]
hub_event+0x1e83/0x4690 drivers/usb/core/hub.c:5735
process_one_work+0x996/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2ef/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff888109b6b000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 0 bytes inside of
2048-byte region [ffff888109b6b000, ffff888109b6b800)

The buggy address belongs to the physical page:
page:ffffea000426da00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109b68
head:ffffea000426da00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x200000000010200(slab|head|node=0|zone=2)
raw: 0200000000010200 0000000000000000 dead000000000001 ffff888100042000
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 1, tgid 1 (swapper/0), ts 3509826111, free_ts 0
prep_new_page mm/page_alloc.c:2456 [inline]
get_page_from_freelist+0x138c/0x27a0 mm/page_alloc.c:4198
__alloc_pages+0x1c7/0x510 mm/page_alloc.c:5426
alloc_page_interleave+0x1e/0x1e0 mm/mempolicy.c:2105
alloc_pages+0x2b1/0x310 mm/mempolicy.c:2267
alloc_slab_page mm/slub.c:1824 [inline]
allocate_slab+0x26c/0x3c0 mm/slub.c:1969
new_slab mm/slub.c:2029 [inline]
___slab_alloc+0x98f/0xda0 mm/slub.c:3031
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
slab_alloc_node mm/slub.c:3209 [inline]
slab_alloc mm/slub.c:3251 [inline]
kmem_cache_alloc_trace+0x2fd/0x3b0 mm/slub.c:3282
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
acpi_os_allocate_zeroed include/acpi/platform/aclinuxex.h:57 [inline]
acpi_ds_create_walk_state+0x88/0x1ff drivers/acpi/acpica/dswstate.c:518
acpi_ps_execute_method+0x19d/0x61c drivers/acpi/acpica/psxface.c:134
acpi_ns_evaluate+0x6c7/0x966 drivers/acpi/acpica/nseval.c:205
acpi_ut_evaluate_object+0xf1/0x3f6 drivers/acpi/acpica/uteval.c:60
acpi_rs_get_method_data+0x7e/0xe5 drivers/acpi/acpica/rsutils.c:650
acpi_walk_resources drivers/acpi/acpica/rsxface.c:616 [inline]
acpi_walk_resources+0xf3/0x1ca drivers/acpi/acpica/rsxface.c:594
__acpi_dev_get_resources drivers/acpi/resource.c:633 [inline]
__acpi_dev_get_resources drivers/acpi/resource.c:614 [inline]
acpi_dev_get_resources+0x1a8/0x230 drivers/acpi/resource.c:671
acpi_device_enumeration_by_parent drivers/acpi/scan.c:1770 [inline]
acpi_init_device_object+0xba1/0x1a30 drivers/acpi/scan.c:1794
page_owner free stack trace missing

Memory state around the buggy address:
ffff888109b6af00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888109b6af80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888109b6b000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888109b6b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888109b6b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 568035b01cfb Linux 6.0-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=156286a5080000
kernel config: https://syzkaller.appspot.com/x/.config?x=e706e91b2a433db

dashboard link: https://syzkaller.appspot.com/bug?extid=f1a69784f6efe748c3bf
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13e5b2f3080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12550915080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f1a697...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline]
BUG: KASAN: use-after-free in send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627

Read of size 4 at addr ffff8880256fb000 by task syz-executor314/4465

CPU: 2 PID: 4465 Comm: syz-executor314 Not tainted 6.0.0-rc1-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014

Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106

print_address_description mm/kasan/report.c:317 [inline]
print_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433
kasan_report+0xb1/0x1e0 mm/kasan/report.c:495

__create_pipe include/linux/usb.h:1945 [inline]
send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627
vfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991

vfs_write+0x2d7/0xdd0 fs/read_write.c:576
ksys_write+0x127/0x250 fs/read_write.c:631

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f7590342b49
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f75902cd308 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f75903c74d8 RCX: 00007f7590342b49

RDX: 0000000000000001 RSI: 0000000020001000 RDI: 0000000000000004

RBP: 00007f75903c74d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f75903c74dc
R13: 00007f7590394328 R14: 0b8b0509005504e1 R15: 0000000000022000
</TASK>

Allocated by task 3757:

kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]

set_alloc_info mm/kasan/common.c:437 [inline]
____kasan_kmalloc mm/kasan/common.c:516 [inline]
____kasan_kmalloc mm/kasan/common.c:475 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:525
kasan_kmalloc include/linux/kasan.h:234 [inline]
kmem_cache_alloc_trace+0x25a/0x460 mm/slab.c:3559

kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
usb_alloc_dev+0x51/0xf00 drivers/usb/core/usb.c:582
hub_port_connect drivers/usb/core/hub.c:5255 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]

hub_event+0x214a/0x4610 drivers/usb/core/hub.c:5735
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Freed by task 3737:

kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370

____kasan_slab_free mm/kasan/common.c:367 [inline]
____kasan_slab_free+0x13d/0x1a0 mm/kasan/common.c:329
kasan_slab_free include/linux/kasan.h:200 [inline]
__cache_free mm/slab.c:3418 [inline]
kfree+0x173/0x390 mm/slab.c:3786
device_release+0x9f/0x240 drivers/base/core.c:2330

kobject_cleanup lib/kobject.c:673 [inline]
kobject_release lib/kobject.c:704 [inline]
kref_put include/linux/kref.h:65 [inline]

kobject_put+0x1be/0x4c0 lib/kobject.c:721
put_device+0x1b/0x30 drivers/base/core.c:3624

hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]

hub_event+0x1f86/0x4610 drivers/usb/core/hub.c:5735
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0x7e/0x90 mm/kasan/generic.c:348
kvfree_call_rcu+0x74/0x940 kernel/rcu/tree.c:3322
free_imon_context+0x15b/0x1f0 drivers/media/rc/imon.c:503
imon_disconnect+0x4b9/0x660 drivers/media/rc/imon.c:2543
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:520 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:512
__device_release_driver drivers/base/dd.c:1209 [inline]
device_release_driver_internal+0x4a1/0x700 drivers/base/dd.c:1235
bus_remove_device+0x2e3/0x590 drivers/base/bus.c:529
device_del+0x4f3/0xc80 drivers/base/core.c:3704
usb_disable_device+0x356/0x7a0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x259/0x6ed drivers/usb/core/hub.c:2235

hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]

hub_event+0x1f86/0x4610 drivers/usb/core/hub.c:5735
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0x7e/0x90 mm/kasan/generic.c:348
call_rcu+0x99/0x790 kernel/rcu/tree.c:2793
netlink_release+0xeff/0x1db0 net/netlink/af_netlink.c:815
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x18/0x20 net/socket.c:1365
__fput+0x277/0x9d0 fs/file_table.c:320
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xad5/0x29b0 kernel/exit.c:795
do_group_exit+0xd2/0x2f0 kernel/exit.c:925
__do_sys_exit_group kernel/exit.c:936 [inline]
__se_sys_exit_group kernel/exit.c:934 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff8880256fb000

which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 0 bytes inside of

2048-byte region [ffff8880256fb000, ffff8880256fb800)

The buggy address belongs to the physical page:

page:ffffea000095bec0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x256fb
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea000089bb88 ffffea0000727fc8 ffff888011840800
raw: 0000000000000000 ffff8880256fb000 0000000100000001 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 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 3133, tgid 3133 (udevd), ts 116180599550, free_ts 116180286761
prep_new_page mm/page_alloc.c:2532 [inline]
get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283
__alloc_pages+0x1c7/0x510 mm/page_alloc.c:5515
__alloc_pages_node include/linux/gfp.h:243 [inline]
kmem_getpages mm/slab.c:1363 [inline]
cache_grow_begin+0x75/0x360 mm/slab.c:2569
cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
____cache_alloc mm/slab.c:3018 [inline]
____cache_alloc mm/slab.c:3001 [inline]
__do_cache_alloc mm/slab.c:3246 [inline]
slab_alloc mm/slab.c:3287 [inline]
__do_kmalloc mm/slab.c:3684 [inline]
__kmalloc+0x3a1/0x4a0 mm/slab.c:3695
kmalloc include/linux/slab.h:605 [inline]
sk_prot_alloc+0x143/0x290 net/core/sock.c:1976
sk_alloc+0x36/0x770 net/core/sock.c:2029
__netlink_create+0x63/0x380 net/netlink/af_netlink.c:647
netlink_create+0x3ad/0x5e0 net/netlink/af_netlink.c:710
__sock_create+0x355/0x790 net/socket.c:1515
sock_create net/socket.c:1566 [inline]
__sys_socket_create net/socket.c:1603 [inline]
__sys_socket_create net/socket.c:1588 [inline]
__sys_socket+0x12f/0x240 net/socket.c:1636
__do_sys_socket net/socket.c:1649 [inline]
__se_sys_socket net/socket.c:1647 [inline]
__x64_sys_socket+0x6f/0xb0 net/socket.c:1647

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1449 [inline]
free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1499
free_unref_page_prepare mm/page_alloc.c:3380 [inline]
free_unref_page+0x19/0x4d0 mm/page_alloc.c:3476
mm_free_pgd kernel/fork.c:737 [inline]
__mmdrop+0xcb/0x3f0 kernel/fork.c:788
mmdrop include/linux/sched/mm.h:50 [inline]
mmdrop_sched include/linux/sched/mm.h:78 [inline]
finish_task_switch.isra.0+0x6cc/0xc70 kernel/sched/core.c:5087
context_switch kernel/sched/core.c:5185 [inline]
__schedule+0xae7/0x52b0 kernel/sched/core.c:6494
schedule+0xda/0x1b0 kernel/sched/core.c:6570
schedule_hrtimeout_range_clock+0x343/0x390 kernel/time/hrtimer.c:2296
ep_poll fs/eventpoll.c:1878 [inline]
do_epoll_wait+0x12ba/0x1950 fs/eventpoll.c:2256
__do_sys_epoll_wait fs/eventpoll.c:2268 [inline]
__se_sys_epoll_wait fs/eventpoll.c:2263 [inline]
__x64_sys_epoll_wait+0x158/0x270 fs/eventpoll.c:2263

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:

ffff8880256faf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880256faf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880256fb000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880256fb080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880256fb100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[Hillf Danton]

On Mon, 15 Aug 2022 09:40:28 -0700

> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 568035b01cfb Linux 6.0-rc1
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=156286a5080000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e706e91b2a433db
> dashboard link: https://syzkaller.appspot.com/bug?extid=f1a69784f6efe748c3bf
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13e5b2f3080000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12550915080000

Acquire ictx->lock to serialize the disconnect path with the open and
write pathes.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 568035b01cfb

--- x/drivers/media/rc/imon.c
+++ i/drivers/media/rc/imon.c
@@ -536,7 +536,7 @@ static int display_open(struct inode *in

mutex_lock(&ictx->lock);

- if (!ictx->display_supported) {
+ if (ictx->disconnected || !ictx->display_supported) {
pr_err("display not supported by device\n");
retval = -ENODEV;
} else if (ictx->display_isopen) {
@@ -598,6 +598,10 @@ static int send_packet(struct imon_conte
int retval = 0;
struct usb_ctrlrequest *control_req = NULL;

+ if (ictx->disconnected)
+ return -ENODEV;
+ if (ictx->tx.busy)
+ return -EBUSY;
/* Check if we need to use control or interrupt urb */
if (!ictx->tx_control) {
pipe = usb_sndintpipe(ictx->usbdev_intf0,
@@ -655,6 +659,7 @@ static int send_packet(struct imon_conte
}
mutex_lock(&ictx->lock);

+ ictx->tx.busy = false;
retval = ictx->tx.status;
if (retval)
pr_err_ratelimited("packet tx failed (%d)\n", retval);
@@ -2498,7 +2503,9 @@ static void imon_disconnect(struct usb_i
int ifnum;

ictx = usb_get_intfdata(interface);
+ mutex_lock(&ictx->lock);
ictx->disconnected = true;
+ mutex_unlock(&ictx->lock);
dev = ictx->dev;
ifnum = interface->cur_altsetting->desc.bInterfaceNumber;

--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+f1a697...@syzkaller.appspotmail.com

Tested on:

commit: 568035b0 Linux 6.0-rc1
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1552c1f3080000

kernel config: https://syzkaller.appspot.com/x/.config?x=e706e91b2a433db
dashboard link: https://syzkaller.appspot.com/bug?extid=f1a69784f6efe748c3bf
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=1452c1f3080000

Note: testing is done by a robot and is best-effort only.