* KASAN: use-after-free Read in string
@ 2018-09-03 21:51 syzbot
2019-01-25 9:41 ` Tetsuo Handa
0 siblings, 1 reply; 7+ messages in thread
From: syzbot @ 2018-09-03 21:51 UTC (permalink / raw)
To: dmitry.torokhov, linux-input, linux-kernel, rydberg, syzkaller-bugs
Hello,
syzbot found the following crash on:
HEAD commit: 58c3f14f86c9 Merge tag 'riscv-for-linus-4.19-rc2' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15506dc1400000
kernel config: https://syzkaller.appspot.com/x/.config?x=531a917630d2a492
dashboard link: https://syzkaller.appspot.com/bug?extid=f648cfb7e0b52bf7ae32
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1178aa46400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11735e0a400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f648cfb7e0b52bf7ae32@syzkaller.appspotmail.com
RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004
RBP: 00000000006cf018 R08: 0000000000000001 R09: 0000000000000038
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000
==================================================================
BUG: KASAN: use-after-free in string+0x2c6/0x2d0 lib/vsprintf.c:604
Read of size 1 at addr ffff8801d79c5080 by task syz-executor215/4685
CPU: 1 PID: 4685 Comm: syz-executor215 Not tainted 4.19.0-rc1+ #215
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+0x1c9/0x2b4 lib/dump_stack.c:113
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412
__asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
string+0x2c6/0x2d0 lib/vsprintf.c:604
vsnprintf+0x48f/0x1b60 lib/vsprintf.c:2293
add_uevent_var+0x140/0x2f0 lib/kobject_uevent.c:659
input_dev_uevent+0x15d/0x860 drivers/input/input.c:1594
dev_uevent+0x340/0x7e0 drivers/base/core.c:1008
kobject_uevent_env+0x45b/0x1110 lib/kobject_uevent.c:547
kobject_uevent+0x1f/0x30 lib/kobject_uevent.c:636
kobject_cleanup lib/kobject.c:649 [inline]
kobject_release lib/kobject.c:691 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put+0x1fb/0x280 lib/kobject.c:708
put_device+0x20/0x30 drivers/base/core.c:2024
input_put_device include/linux/input.h:349 [inline]
evdev_free+0x4f/0x70 drivers/input/evdev.c:369
device_release+0x7e/0x210 drivers/base/core.c:891
kobject_cleanup lib/kobject.c:662 [inline]
kobject_release lib/kobject.c:691 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put+0x194/0x280 lib/kobject.c:708
cdev_default_release+0x3e/0x50 fs/char_dev.c:607
kobject_cleanup lib/kobject.c:662 [inline]
kobject_release lib/kobject.c:691 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put+0x194/0x280 lib/kobject.c:708
cdev_put.part.0+0x36/0x50 fs/char_dev.c:368
cdev_put+0x1f/0x30 fs/char_dev.c:366
__fput+0x8ae/0xa40 fs/file_table.c:281
____fput+0x15/0x20 fs/file_table.c:309
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x1ae4/0x26e0 kernel/exit.c:867
do_group_exit+0x177/0x440 kernel/exit.c:970
__do_sys_exit_group kernel/exit.c:981 [inline]
__se_sys_exit_group kernel/exit.c:979 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443a68
Code: Bad RIP value.
RSP: 002b:00007fff70261298 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443a68
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004c39c8 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d5180 R14: 0000000000000000 R15: 0000000000000000
Allocated by task 4685:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
__do_kmalloc mm/slab.c:3718 [inline]
__kmalloc_track_caller+0x14a/0x720 mm/slab.c:3733
kstrndup+0x5f/0xe0 mm/util.c:98
uinput_setup_device_legacy drivers/input/misc/uinput.c:549 [inline]
uinput_write+0x2fb/0x1120 drivers/input/misc/uinput.c:621
__vfs_write+0x117/0x9d0 fs/read_write.c:485
vfs_write+0x1fc/0x560 fs/read_write.c:549
ksys_write+0x101/0x260 fs/read_write.c:598
__do_sys_write fs/read_write.c:610 [inline]
__se_sys_write fs/read_write.c:607 [inline]
__x64_sys_write+0x73/0xb0 fs/read_write.c:607
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 4685:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xd9/0x210 mm/slab.c:3813
uinput_destroy_device+0xf8/0x250 drivers/input/misc/uinput.c:310
uinput_ioctl_handler.isra.10+0x1439/0x2540 drivers/input/misc/uinput.c:880
uinput_ioctl+0x4c/0x60 drivers/input/misc/uinput.c:1047
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff8801d79c5080
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
32-byte region [ffff8801d79c5080, ffff8801d79c50a0)
The buggy address belongs to the page:
page:ffffea00075e7140 count:1 mapcount:0 mapping:ffff8801dac001c0
index:0xffff8801d79c5fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00075e0908 ffffea00075e7408 ffff8801dac001c0
raw: ffff8801d79c5fc1 ffff8801d79c5000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801d79c4f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8801d79c5000: 00 00 fc fc fc fc fc fc 00 00 00 fc fc fc fc fc
> ffff8801d79c5080: fb fb fb fb fc fc fc fc 07 fc fc fc fc fc fc fc
^
ffff8801d79c5100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
ffff8801d79c5180: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================
---
This bug is generated by a bot. It may contain errors.
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: KASAN: use-after-free Read in string 2018-09-03 21:51 KASAN: use-after-free Read in string syzbot @ 2019-01-25 9:41 ` Tetsuo Handa 0 siblings, 0 replies; 7+ messages in thread From: Tetsuo Handa @ 2019-01-25 9:41 UTC (permalink / raw) To: dmitry.torokhov, rydberg Cc: syzbot, linux-input, linux-kernel, syzkaller-bugs Hello. syzbot is hitting use-after-free bug in uinput module. It seems that syzbot is hitting this bug from cdev_put() path when closing a character file. But since I can't reproduce the problem, I used a debug patch which raises the refcount as if the character device file is open()ed before uinput_destroy_device() is called. ---------------------------------------- diff --git a/drivers/input/input.c b/drivers/input/input.c index 3304aaaffe87..45fab285f189 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1594,6 +1594,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env) INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name); if (dev->phys) INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys); + WARN_ON(!kref_read(&device->kobj.kref)); if (dev->uniq) INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq); diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..0374ea00d4cc 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -299,8 +299,11 @@ static void uinput_destroy_device(struct uinput_device *udev) udev->state = UIST_NEW_DEVICE; if (dev) { + struct input_dev *d = input_get_device(dev); name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); @@ -310,6 +313,7 @@ static void uinput_destroy_device(struct uinput_device *udev) kfree(name); kfree(phys); udev->dev = NULL; + input_put_device(d); } } ---------------------------------------- I can sometimes observe WARN_ON() because input_put_device() drops the refcount to 0. ---------------------------------------- [ 122.491394][ T7080] kobject: 'input32' (00000000de092799): kobject_add_internal: parent: 'input', set: 'devices' [ 122.497790][ T7080] kobject: 'input32' (00000000de092799): kobject_uevent_env [ 122.501716][ T7080] kobject: 'input32' (00000000de092799): fill_kobj_path: path = '/devices/virtual/input/input32' [ 122.510123][ T7080] kobject: 'input32' (00000000de092799): fill_kobj_path: path = '/devices/virtual/input/input32' [ 122.517230][ T7080] input: syz1 as /devices/virtual/input/input32 [ 122.522334][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_add_internal: parent: 'input32', set: 'devices' [ 122.531090][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_uevent_env [ 122.536589][ T7080] kobject: 'event3' (00000000317a3ed6): fill_kobj_path: path = '/devices/virtual/input/input32/event3' [ 122.545052][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_uevent_env [ 122.549900][ T7080] kobject: 'event3' (00000000317a3ed6): fill_kobj_path: path = '/devices/virtual/input/input32/event3' [ 122.557276][ T7080] FAULT_INJECTION: forcing a failure. [ 122.557276][ T7080] name failslab, interval 1, probability 0, space 0, times 0 [ 122.564580][ T7080] CPU: 0 PID: 7080 Comm: a.out Tainted: G W 5.0.0-rc3+ #142 [ 122.569018][ T7080] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 122.576320][ T7080] Call Trace: [ 122.579087][ T7080] dump_stack+0x154/0x1c5 [ 122.582643][ T7080] should_fail+0x61e/0x720 [ 122.585679][ T7080] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 122.589436][ T7080] ? lock_downgrade+0x880/0x880 [ 122.592499][ T7080] ? ___might_sleep+0x2fe/0x480 [ 122.595518][ T7080] __should_failslab+0xec/0x120 [ 122.598995][ T7080] should_failslab+0x9/0x14 [ 122.601869][ T7080] kmem_cache_alloc+0x47/0x710 [ 122.605051][ T7080] ? refcount_add_not_zero_checked+0x1f0/0x1f0 [ 122.608359][ T7080] ? netlink_broadcast_filtered+0x6c/0xa30 [ 122.611721][ T7080] skb_clone+0x122/0x360 [ 122.614463][ T7080] netlink_broadcast_filtered+0x793/0xa30 [ 122.617568][ T7080] netlink_broadcast+0x3e/0x50 [ 122.620668][ T7080] kobject_uevent_env+0xd51/0x1150 [ 122.623565][ T7080] ? wait_for_completion+0x400/0x400 [ 122.626488][ T7080] kobject_uevent+0x1f/0x30 [ 122.629334][ T7080] device_del+0x673/0xaf0 [ 122.631925][ T7080] ? __device_links_no_driver+0x230/0x230 [ 122.634885][ T7080] ? mark_held_locks+0xaf/0x100 [ 122.637857][ T7080] ? _raw_spin_unlock_irq+0x27/0x80 [ 122.640594][ T7080] ? __input_unregister_device+0x13b/0x480 [ 122.643650][ T7080] ? _raw_spin_unlock_irq+0x27/0x80 [ 122.646334][ T7080] cdev_device_del+0x1a/0x70 [ 122.648825][ T7080] evdev_disconnect+0x42/0xb0 [ 122.651291][ T7080] __input_unregister_device+0x1e3/0x480 [ 122.654279][ T7080] ? kasan_check_read+0x11/0x20 [ 122.656777][ T7080] input_unregister_device+0xa4/0xe0 [ 122.659590][ T7080] uinput_destroy_device+0x216/0x270 [ 122.662130][ T7080] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 122.664850][ T7080] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 122.667560][ T7080] ? kasan_check_write+0x14/0x20 [ 122.670157][ T7080] ? proc_fail_nth_write+0x94/0x1c0 [ 122.672623][ T7080] ? map_files_get_link+0x3c0/0x3c0 [ 122.675253][ T7080] ? __handle_mm_fault+0x20c0/0x3290 [ 122.677842][ T7080] ? map_files_get_link+0x3c0/0x3c0 [ 122.680187][ T7080] ? __vfs_write+0x111/0x7f0 [ 122.682372][ T7080] uinput_ioctl+0x4c/0x60 [ 122.684486][ T7080] ? uinput_compat_ioctl+0x80/0x80 [ 122.687204][ T7080] do_vfs_ioctl+0x1a9/0x1100 [ 122.689530][ T7080] ? ioctl_preallocate+0x1e0/0x1e0 [ 122.691855][ T7080] ? lock_downgrade+0x880/0x880 [ 122.694111][ T7080] ? check_preemption_disabled+0x3b/0x240 [ 122.696603][ T7080] ? __sb_end_write+0xc6/0x100 [ 122.698842][ T7080] ? vfs_write+0x224/0x4d0 [ 122.700991][ T7080] ? kasan_check_read+0x11/0x20 [ 122.703610][ T7080] ? security_file_ioctl+0x87/0xb0 [ 122.706099][ T7080] ksys_ioctl+0x94/0xb0 [ 122.708161][ T7080] __x64_sys_ioctl+0x73/0xb0 [ 122.710525][ T7080] do_syscall_64+0xe7/0x570 [ 122.712669][ T7080] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 122.715185][ T7080] RIP: 0033:0x7f5160b1a839 [ 122.717311][ T7080] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 122.727007][ T7080] RSP: 002b:00007ffe75b27308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 122.731413][ T7080] RAX: ffffffffffffffda RBX: 00007ffe75b27310 RCX: 00007f5160b1a839 [ 122.735723][ T7080] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 122.739593][ T7080] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f5160e00038 [ 122.742850][ T7080] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 122.746101][ T7080] R13: 00007ffe75b27420 R14: 0000000000000000 R15: 0000000000000000 [ 122.750271][ T7080] kobject: '(null)' (00000000eccc95ba): kobject_cleanup, parent 00000000317a3ed6 [ 122.757125][ T7080] kobject: '(null)' (00000000eccc95ba): calling ktype release [ 122.876948][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_cleanup, parent (null) [ 122.882151][ T7080] kobject: 'event3' (00000000317a3ed6): calling ktype release [ 122.885425][ T7080] kobject: 'event3': free name [ 122.888374][ T7080] kobject: 'input32' (00000000de092799): kobject_uevent_env [ 122.891710][ T7080] kobject: 'input32' (00000000de092799): fill_kobj_path: path = '/devices/virtual/input/input32' [ 122.897786][ T7080] kobject: 'input32' (00000000de092799): kobject_cleanup, parent (null) [ 122.903563][ T7080] kobject: 'input32' (00000000de092799): calling ktype release [ 122.907255][ T7080] kobject: 'input32': free name [ 122.923983][ T7085] kobject: 'input33' (000000007fe64e92): kobject_add_internal: parent: 'input', set: 'devices' [ 122.933592][ T7085] kobject: 'input33' (000000007fe64e92): kobject_uevent_env [ 122.939795][ T7085] kobject: 'input33' (000000007fe64e92): fill_kobj_path: path = '/devices/virtual/input/input33' [ 122.946505][ T7085] kobject: 'input33' (000000007fe64e92): fill_kobj_path: path = '/devices/virtual/input/input33' [ 122.956466][ T7085] input: syz1 as /devices/virtual/input/input33 [ 122.961981][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_add_internal: parent: 'input33', set: 'devices' [ 122.970126][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_uevent_env [ 122.974416][ T7085] kobject: 'event3' (000000003c8d2a0d): fill_kobj_path: path = '/devices/virtual/input/input33/event3' [ 122.982226][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_uevent_env [ 122.986290][ T7085] kobject: 'event3' (000000003c8d2a0d): fill_kobj_path: path = '/devices/virtual/input/input33/event3' [ 122.994321][ T7085] kobject: '(null)' (00000000263f9149): kobject_cleanup, parent 000000003c8d2a0d [ 123.001522][ T7085] kobject: '(null)' (00000000263f9149): calling ktype release [ 123.041730][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_cleanup, parent (null) [ 123.047963][ T7085] kobject: 'event3' (000000003c8d2a0d): calling ktype release [ 123.052144][ T7085] kobject: 'event3': free name [ 123.055887][ T7085] kobject: 'input33' (000000007fe64e92): kobject_uevent_env [ 123.059898][ T7085] FAULT_INJECTION: forcing a failure. [ 123.059898][ T7085] name failslab, interval 1, probability 0, space 0, times 0 [ 123.067534][ T7085] CPU: 2 PID: 7085 Comm: a.out Tainted: G W 5.0.0-rc3+ #142 [ 123.073308][ T7085] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 123.081085][ T7085] Call Trace: [ 123.084204][ T7085] dump_stack+0x154/0x1c5 [ 123.087890][ T7085] should_fail+0x61e/0x720 [ 123.091337][ T7085] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 123.096751][ T7085] ? lock_downgrade+0x880/0x880 [ 123.102104][ T7085] ? ___might_sleep+0x2fe/0x480 [ 123.107205][ T7085] __should_failslab+0xec/0x120 [ 123.112120][ T7085] should_failslab+0x9/0x14 [ 123.116677][ T7085] kmem_cache_alloc_trace+0x4b/0x710 [ 123.121206][ T7085] ? dev_uevent_filter+0xe0/0xe0 [ 123.124370][ T7085] kobject_uevent_env+0x22c/0x1150 [ 123.127605][ T7085] ? wait_for_completion+0x400/0x400 [ 123.130996][ T7085] ? software_node_notify+0xd8/0x2b0 [ 123.134068][ T7085] kobject_uevent+0x1f/0x30 [ 123.137137][ T7085] device_del+0x673/0xaf0 [ 123.140102][ T7085] ? __device_links_no_driver+0x230/0x230 [ 123.143361][ T7085] ? trace_hardirqs_on+0x52/0x1d0 [ 123.146222][ T7085] __input_unregister_device+0x379/0x480 [ 123.149280][ T7085] ? kasan_check_read+0x11/0x20 [ 123.152249][ T7085] input_unregister_device+0xa4/0xe0 [ 123.155458][ T7085] uinput_destroy_device+0x216/0x270 [ 123.158365][ T7085] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 123.161375][ T7085] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 123.164555][ T7085] ? kasan_check_write+0x14/0x20 [ 123.167372][ T7085] ? proc_fail_nth_write+0x94/0x1c0 [ 123.170416][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.174171][ T7085] ? __handle_mm_fault+0x20c0/0x3290 [ 123.177902][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.181524][ T7085] ? __vfs_write+0x111/0x7f0 [ 123.184877][ T7085] uinput_ioctl+0x4c/0x60 [ 123.188445][ T7085] ? uinput_compat_ioctl+0x80/0x80 [ 123.191368][ T7085] do_vfs_ioctl+0x1a9/0x1100 [ 123.193809][ T7085] ? ioctl_preallocate+0x1e0/0x1e0 [ 123.196311][ T7085] ? lock_downgrade+0x880/0x880 [ 123.199013][ T7085] ? check_preemption_disabled+0x3b/0x240 [ 123.201867][ T7085] ? __sb_end_write+0xc6/0x100 [ 123.204412][ T7085] ? vfs_write+0x224/0x4d0 [ 123.206756][ T7085] ? kasan_check_read+0x11/0x20 [ 123.209168][ T7085] ? security_file_ioctl+0x87/0xb0 [ 123.211779][ T7085] ksys_ioctl+0x94/0xb0 [ 123.214142][ T7085] __x64_sys_ioctl+0x73/0xb0 [ 123.216377][ T7085] do_syscall_64+0xe7/0x570 [ 123.218674][ T7085] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 123.221573][ T7085] RIP: 0033:0x7fd9b2d0d839 [ 123.223703][ T7085] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 123.233417][ T7085] RSP: 002b:00007fff66a27408 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 123.237353][ T7085] RAX: ffffffffffffffda RBX: 00007fff66a27410 RCX: 00007fd9b2d0d839 [ 123.241290][ T7085] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 123.246692][ T7085] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007fd9b2ff0038 [ 123.250315][ T7085] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 123.254325][ T7085] R13: 00007fff66a27520 R14: 0000000000000000 R15: 0000000000000000 [ 123.258552][ T7085] kobject: 'input33' (000000007fe64e92): kobject_cleanup, parent (null) [ 123.263643][ T7085] kobject: 'input33' (000000007fe64e92): auto cleanup 'remove' event [ 123.267107][ T7085] kobject: 'input33' (000000007fe64e92): kobject_uevent_env [ 123.270908][ T7085] kobject: 'input33' (000000007fe64e92): fill_kobj_path: path = '/input33' [ 123.274726][ T7085] WARNING: CPU: 2 PID: 7085 at drivers/input/input.c:1597 input_dev_uevent+0x5a2/0x7b0 [ 123.280249][ T7085] Modules linked in: [ 123.282624][ T7085] CPU: 2 PID: 7085 Comm: a.out Tainted: G W 5.0.0-rc3+ #142 [ 123.286383][ T7085] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 123.292981][ T7085] RIP: 0010:input_dev_uevent+0x5a2/0x7b0 [ 123.296185][ T7085] Code: e8 53 5b 25 fd 44 8b 4d d4 e9 03 fb ff ff e8 45 5b 25 fd e9 c2 fa ff ff 4c 89 ef e8 58 5b 25 fd e9 52 fc ff ff e8 6e 62 f3 fc <0f> 0b e9 51 fc ff ff e8 62 62 f3 fc 49 8d 54 24 30 b9 ff 02 00 00 [ 123.306200][ T7085] RSP: 0018:ffff8881e2187830 EFLAGS: 00010293 [ 123.309423][ T7085] RAX: ffff8881de5a6180 RBX: ffff8881df2c6e88 RCX: ffffffff8475e852 [ 123.313674][ T7085] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881df2c6ed0 [ 123.319246][ T7085] RBP: ffff8881e2187868 R08: ffffed103be58ddb R09: ffffed103be58ddb [ 123.324930][ T7085] R10: 0000000000000001 R11: ffffed103be58dda R12: ffff8881df2c6bc0 [ 123.330307][ T7085] R13: ffff8881df2c6ed0 R14: ffff8881dd3a6940 R15: ffff8881df2c6e88 [ 123.334329][ T7085] FS: 00007fd9b31fd500(0000) GS:ffff8881f5a80000(0000) knlGS:0000000000000000 [ 123.338555][ T7085] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 123.342050][ T7085] CR2: 00007fd9b2d9fb24 CR3: 00000001c370e002 CR4: 00000000003606e0 [ 123.345922][ T7085] Call Trace: [ 123.348590][ T7085] ? input_add_uevent_bm_var+0x130/0x130 [ 123.351864][ T7085] dev_uevent+0x330/0x5e0 [ 123.355017][ T7085] ? device_get_devnode+0x2e0/0x2e0 [ 123.358047][ T7085] ? vprintk_func+0x68/0x190 [ 123.360969][ T7085] ? add_uevent_var+0x20c/0x2f0 [ 123.363992][ T7085] ? cleanup_uevent_env+0x50/0x50 [ 123.366933][ T7085] ? kobject_uevent_env+0x347/0x1150 [ 123.370025][ T7085] ? device_get_devnode+0x2e0/0x2e0 [ 123.372997][ T7085] kobject_uevent_env+0x487/0x1150 [ 123.375921][ T7085] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 123.378942][ T7085] kobject_uevent+0x1f/0x30 [ 123.381699][ T7085] kobject_put+0x33c/0x400 [ 123.384375][ T7085] put_device+0x20/0x30 [ 123.387304][ T7085] uinput_destroy_device+0x158/0x270 [ 123.390182][ T7085] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 123.393163][ T7085] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 123.397616][ T7085] ? kasan_check_write+0x14/0x20 [ 123.401440][ T7085] ? proc_fail_nth_write+0x94/0x1c0 [ 123.404393][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.407191][ T7085] ? __handle_mm_fault+0x20c0/0x3290 [ 123.410014][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.412668][ T7085] ? __vfs_write+0x111/0x7f0 [ 123.415202][ T7085] uinput_ioctl+0x4c/0x60 [ 123.417633][ T7085] ? uinput_compat_ioctl+0x80/0x80 [ 123.420355][ T7085] do_vfs_ioctl+0x1a9/0x1100 [ 123.423053][ T7085] ? ioctl_preallocate+0x1e0/0x1e0 [ 123.425574][ T7085] ? lock_downgrade+0x880/0x880 [ 123.427945][ T7085] ? check_preemption_disabled+0x3b/0x240 [ 123.430867][ T7085] ? __sb_end_write+0xc6/0x100 [ 123.433322][ T7085] ? vfs_write+0x224/0x4d0 [ 123.435527][ T7085] ? kasan_check_read+0x11/0x20 [ 123.438404][ T7085] ? security_file_ioctl+0x87/0xb0 [ 123.440847][ T7085] ksys_ioctl+0x94/0xb0 [ 123.442940][ T7085] __x64_sys_ioctl+0x73/0xb0 [ 123.445627][ T7085] do_syscall_64+0xe7/0x570 [ 123.447876][ T7085] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 123.450354][ T7085] RIP: 0033:0x7fd9b2d0d839 [ 123.452589][ T7085] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 123.461381][ T7085] RSP: 002b:00007fff66a27408 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 123.464806][ T7085] RAX: ffffffffffffffda RBX: 00007fff66a27410 RCX: 00007fd9b2d0d839 [ 123.468105][ T7085] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 123.471712][ T7085] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007fd9b2ff0038 [ 123.475028][ T7085] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 123.478476][ T7085] R13: 00007fff66a27520 R14: 0000000000000000 R15: 0000000000000000 [ 123.481837][ T7085] irq event stamp: 2904 [ 123.484128][ T7085] hardirqs last enabled at (2903): [<ffffffff81552310>] console_unlock+0x670/0xd00 [ 123.489864][ T7085] hardirqs last disabled at (2904): [<ffffffff81006087>] trace_hardirqs_off_thunk+0x1a/0x1c [ 123.496220][ T7085] softirqs last enabled at (2888): [<ffffffff86c00673>] __do_softirq+0x673/0x987 [ 123.501609][ T7085] softirqs last disabled at (2869): [<ffffffff8140c0f5>] irq_exit+0x195/0x1c0 [ 123.505845][ T7085] ---[ end trace de7fa7a05c9c270b ]--- [ 123.509700][ T7085] kobject: 'input33' (000000007fe64e92): calling ktype release [ 123.514678][ T7085] kobject: 'input33': free name ---------------------------------------- I also tried reproducing the problem without raising the refcount, ---------------------------------------- diff --git a/drivers/input/input.c b/drivers/input/input.c index 3304aaaffe87..45fab285f189 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1594,6 +1594,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env) INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name); if (dev->phys) INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys); + WARN_ON(!kref_read(&device->kobj.kref)); if (dev->uniq) INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq); diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..131591b5babd 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -300,7 +300,9 @@ static void uinput_destroy_device(struct uinput_device *udev) if (dev) { name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); ---------------------------------------- and I can sometimes observe WARN_ON() because the refcount drops to 0. Therefore, I think that we must not assume that kobject_uevent() won't be called after uinput_destroy_device() called kfree(). ---------------------------------------- [ 96.531017][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_add_internal: parent: 'input', set: 'devices' [ 96.537254][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_uevent_env [ 96.541162][ T6997] kobject: 'input21' (0000000074dfd11f): fill_kobj_path: path = '/devices/virtual/input/input21' [ 96.547745][ T6997] kobject: 'input21' (0000000074dfd11f): fill_kobj_path: path = '/devices/virtual/input/input21' [ 96.554230][ T6997] input: syz1 as /devices/virtual/input/input21 [ 96.559539][ T6997] kobject: 'event3' (00000000648730df): kobject_add_internal: parent: 'input21', set: 'devices' [ 96.569883][ T6997] kobject: 'event3' (00000000648730df): kobject_uevent_env [ 96.574314][ T6997] kobject: 'event3' (00000000648730df): fill_kobj_path: path = '/devices/virtual/input/input21/event3' [ 96.584282][ T6997] kobject: 'event3' (00000000648730df): kobject_uevent_env [ 96.588860][ T6997] kobject: 'event3' (00000000648730df): fill_kobj_path: path = '/devices/virtual/input/input21/event3' [ 96.599355][ T6997] FAULT_INJECTION: forcing a failure. [ 96.599355][ T6997] name failslab, interval 1, probability 0, space 0, times 0 [ 96.607828][ T6997] CPU: 3 PID: 6997 Comm: a.out Not tainted 5.0.0-rc3+ #143 [ 96.611875][ T6997] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 96.619039][ T6997] Call Trace: [ 96.622211][ T6997] dump_stack+0x154/0x1c5 [ 96.625318][ T6997] should_fail+0x61e/0x720 [ 96.628678][ T6997] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 96.632461][ T6997] ? lock_downgrade+0x880/0x880 [ 96.635613][ T6997] ? ___might_sleep+0x2fe/0x480 [ 96.638996][ T6997] __should_failslab+0xec/0x120 [ 96.642133][ T6997] should_failslab+0x9/0x14 [ 96.645003][ T6997] kmem_cache_alloc+0x47/0x710 [ 96.648132][ T6997] ? refcount_add_not_zero_checked+0x1f0/0x1f0 [ 96.651502][ T6997] ? netlink_broadcast_filtered+0x6c/0xa30 [ 96.654754][ T6997] skb_clone+0x122/0x360 [ 96.657877][ T6997] netlink_broadcast_filtered+0x793/0xa30 [ 96.661063][ T6997] netlink_broadcast+0x3e/0x50 [ 96.663850][ T6997] kobject_uevent_env+0xd51/0x1150 [ 96.666808][ T6997] ? wait_for_completion+0x400/0x400 [ 96.669819][ T6997] kobject_uevent+0x1f/0x30 [ 96.672838][ T6997] device_del+0x673/0xaf0 [ 96.675412][ T6997] ? __device_links_no_driver+0x230/0x230 [ 96.678471][ T6997] ? mark_held_locks+0xaf/0x100 [ 96.681207][ T6997] ? _raw_spin_unlock_irq+0x27/0x80 [ 96.683928][ T6997] ? __input_unregister_device+0x13b/0x480 [ 96.686962][ T6997] ? _raw_spin_unlock_irq+0x27/0x80 [ 96.689979][ T6997] cdev_device_del+0x1a/0x70 [ 96.692532][ T6997] evdev_disconnect+0x42/0xb0 [ 96.695109][ T6997] __input_unregister_device+0x1e3/0x480 [ 96.697885][ T6997] ? kasan_check_read+0x11/0x20 [ 96.700421][ T6997] input_unregister_device+0xa4/0xe0 [ 96.702971][ T6997] uinput_destroy_device+0x1e3/0x240 [ 96.705894][ T6997] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 96.708713][ T6997] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 96.711453][ T6997] ? kasan_check_write+0x14/0x20 [ 96.713866][ T6997] ? proc_fail_nth_write+0x94/0x1c0 [ 96.716386][ T6997] ? map_files_get_link+0x3c0/0x3c0 [ 96.718808][ T6997] ? __handle_mm_fault+0x20c0/0x3290 [ 96.721446][ T6997] ? map_files_get_link+0x3c0/0x3c0 [ 96.724169][ T6997] ? __vfs_write+0x111/0x7f0 [ 96.726353][ T6997] uinput_ioctl+0x4c/0x60 [ 96.728983][ T6997] ? uinput_compat_ioctl+0x80/0x80 [ 96.732259][ T6997] do_vfs_ioctl+0x1a9/0x1100 [ 96.735345][ T6997] ? ioctl_preallocate+0x1e0/0x1e0 [ 96.738758][ T6997] ? lock_downgrade+0x880/0x880 [ 96.741859][ T6997] ? check_preemption_disabled+0x3b/0x240 [ 96.744752][ T6997] ? __sb_end_write+0xc6/0x100 [ 96.747207][ T6997] ? vfs_write+0x224/0x4d0 [ 96.750131][ T6997] ? kasan_check_read+0x11/0x20 [ 96.753300][ T6997] ? security_file_ioctl+0x87/0xb0 [ 96.756922][ T6997] ksys_ioctl+0x94/0xb0 [ 96.759615][ T6997] __x64_sys_ioctl+0x73/0xb0 [ 96.761779][ T6997] do_syscall_64+0xe7/0x570 [ 96.764036][ T6997] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 96.766695][ T6997] RIP: 0033:0x7f02ca03a839 [ 96.768823][ T6997] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 96.777498][ T6997] RSP: 002b:00007ffe08c4e418 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 96.780999][ T6997] RAX: ffffffffffffffda RBX: 00007ffe08c4e420 RCX: 00007f02ca03a839 [ 96.784750][ T6997] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 96.788895][ T6997] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f02ca320038 [ 96.792533][ T6997] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 96.796682][ T6997] R13: 00007ffe08c4e530 R14: 0000000000000000 R15: 0000000000000000 [ 96.802099][ T6997] kobject: '(null)' (0000000056da26df): kobject_cleanup, parent 00000000648730df [ 96.808680][ T6997] kobject: '(null)' (0000000056da26df): calling ktype release [ 96.856008][ T6997] kobject: 'event3' (00000000648730df): kobject_cleanup, parent (null) [ 96.863416][ T6997] kobject: 'event3' (00000000648730df): calling ktype release [ 96.868646][ T6997] kobject: 'event3': free name [ 96.871768][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_uevent_env [ 96.876871][ T6997] kobject: 'input21' (0000000074dfd11f): fill_kobj_path: path = '/devices/virtual/input/input21' [ 96.884436][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_cleanup, parent (null) [ 96.891397][ T6997] kobject: 'input21' (0000000074dfd11f): calling ktype release [ 96.896877][ T6997] kobject: 'input21': free name [ 106.244899][ T7002] kobject: 'input22' (00000000e09f1862): kobject_add_internal: parent: 'input', set: 'devices' [ 106.251101][ T7002] kobject: 'input22' (00000000e09f1862): kobject_uevent_env [ 106.255895][ T7002] kobject: 'input22' (00000000e09f1862): fill_kobj_path: path = '/devices/virtual/input/input22' [ 106.262394][ T7002] kobject: 'input22' (00000000e09f1862): fill_kobj_path: path = '/devices/virtual/input/input22' [ 106.269457][ T7002] input: syz1 as /devices/virtual/input/input22 [ 106.273526][ T7002] kobject: 'event3' (000000006eb448c2): kobject_add_internal: parent: 'input22', set: 'devices' [ 106.281027][ T7002] kobject: 'event3' (000000006eb448c2): kobject_uevent_env [ 106.285352][ T7002] kobject: 'event3' (000000006eb448c2): fill_kobj_path: path = '/devices/virtual/input/input22/event3' [ 106.293562][ T7002] kobject: 'event3' (000000006eb448c2): kobject_uevent_env [ 106.297761][ T7002] kobject: 'event3' (000000006eb448c2): fill_kobj_path: path = '/devices/virtual/input/input22/event3' [ 106.305312][ T7002] kobject: '(null)' (00000000192e3ebd): kobject_cleanup, parent 000000006eb448c2 [ 106.314030][ T7002] kobject: '(null)' (00000000192e3ebd): calling ktype release [ 106.404201][ T7002] kobject: 'event3' (000000006eb448c2): kobject_cleanup, parent (null) [ 106.410653][ T7002] kobject: 'event3' (000000006eb448c2): calling ktype release [ 106.414781][ T7002] kobject: 'event3': free name [ 106.418206][ T7002] kobject: 'input22' (00000000e09f1862): kobject_uevent_env [ 106.422387][ T7002] FAULT_INJECTION: forcing a failure. [ 106.422387][ T7002] name failslab, interval 1, probability 0, space 0, times 0 [ 106.429765][ T7002] CPU: 0 PID: 7002 Comm: a.out Not tainted 5.0.0-rc3+ #143 [ 106.433704][ T7002] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 106.440953][ T7002] Call Trace: [ 106.443818][ T7002] dump_stack+0x154/0x1c5 [ 106.446842][ T7002] should_fail+0x61e/0x720 [ 106.449962][ T7002] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 106.453392][ T7002] ? lock_downgrade+0x880/0x880 [ 106.456771][ T7002] ? ___might_sleep+0x2fe/0x480 [ 106.459873][ T7002] __should_failslab+0xec/0x120 [ 106.462960][ T7002] should_failslab+0x9/0x14 [ 106.465843][ T7002] kmem_cache_alloc_trace+0x4b/0x710 [ 106.469001][ T7002] ? dev_uevent_filter+0xe0/0xe0 [ 106.472264][ T7002] kobject_uevent_env+0x22c/0x1150 [ 106.475338][ T7002] ? wait_for_completion+0x400/0x400 [ 106.478399][ T7002] ? software_node_notify+0xd8/0x2b0 [ 106.481321][ T7002] kobject_uevent+0x1f/0x30 [ 106.484081][ T7002] device_del+0x673/0xaf0 [ 106.486758][ T7002] ? __device_links_no_driver+0x230/0x230 [ 106.489994][ T7002] ? trace_hardirqs_on+0x52/0x1d0 [ 106.492762][ T7002] __input_unregister_device+0x379/0x480 [ 106.495713][ T7002] ? kasan_check_read+0x11/0x20 [ 106.498448][ T7002] input_unregister_device+0xa4/0xe0 [ 106.501178][ T7002] uinput_destroy_device+0x1e3/0x240 [ 106.504219][ T7002] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 106.507369][ T7002] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 106.510320][ T7002] ? kasan_check_write+0x14/0x20 [ 106.512855][ T7002] ? proc_fail_nth_write+0x94/0x1c0 [ 106.515504][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.518111][ T7002] ? __handle_mm_fault+0x20c0/0x3290 [ 106.520647][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.523352][ T7002] ? __vfs_write+0x111/0x7f0 [ 106.525728][ T7002] uinput_ioctl+0x4c/0x60 [ 106.527934][ T7002] ? uinput_compat_ioctl+0x80/0x80 [ 106.530418][ T7002] do_vfs_ioctl+0x1a9/0x1100 [ 106.532667][ T7002] ? ioctl_preallocate+0x1e0/0x1e0 [ 106.535138][ T7002] ? lock_downgrade+0x880/0x880 [ 106.537821][ T7002] ? check_preemption_disabled+0x3b/0x240 [ 106.541370][ T7002] ? __sb_end_write+0xc6/0x100 [ 106.544464][ T7002] ? vfs_write+0x224/0x4d0 [ 106.547441][ T7002] ? kasan_check_read+0x11/0x20 [ 106.550570][ T7002] ? security_file_ioctl+0x87/0xb0 [ 106.553765][ T7002] ksys_ioctl+0x94/0xb0 [ 106.556910][ T7002] __x64_sys_ioctl+0x73/0xb0 [ 106.559835][ T7002] do_syscall_64+0xe7/0x570 [ 106.562861][ T7002] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 106.566361][ T7002] RIP: 0033:0x7f5185ef6839 [ 106.569153][ T7002] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 106.577796][ T7002] RSP: 002b:00007ffc7a800078 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 106.581248][ T7002] RAX: ffffffffffffffda RBX: 00007ffc7a800080 RCX: 00007f5185ef6839 [ 106.584590][ T7002] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 106.588145][ T7002] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f51861d0038 [ 106.591466][ T7002] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 106.594767][ T7002] R13: 00007ffc7a800190 R14: 0000000000000000 R15: 0000000000000000 [ 106.598818][ T7002] kobject: 'input22' (00000000e09f1862): kobject_cleanup, parent (null) [ 106.603916][ T7002] kobject: 'input22' (00000000e09f1862): auto cleanup 'remove' event [ 106.607654][ T7002] kobject: 'input22' (00000000e09f1862): kobject_uevent_env [ 106.610810][ T7002] kobject: 'input22' (00000000e09f1862): fill_kobj_path: path = '/input22' [ 106.614563][ T7002] WARNING: CPU: 0 PID: 7002 at drivers/input/input.c:1597 input_dev_uevent+0x5a2/0x7b0 [ 106.619879][ T7002] Modules linked in: [ 106.622530][ T7002] CPU: 0 PID: 7002 Comm: a.out Not tainted 5.0.0-rc3+ #143 [ 106.625853][ T7002] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 106.631813][ T7002] RIP: 0010:input_dev_uevent+0x5a2/0x7b0 [ 106.634771][ T7002] Code: e8 53 5b 25 fd 44 8b 4d d4 e9 03 fb ff ff e8 45 5b 25 fd e9 c2 fa ff ff 4c 89 ef e8 58 5b 25 fd e9 52 fc ff ff e8 6e 62 f3 fc <0f> 0b e9 51 fc ff ff e8 62 62 f3 fc 49 8d 54 24 30 b9 ff 02 00 00 [ 106.644676][ T7002] RSP: 0018:ffff8881d14af828 EFLAGS: 00010293 [ 106.648039][ T7002] RAX: ffff8881d287c300 RBX: ffff8881f06ab748 RCX: ffffffff8475e852 [ 106.651852][ T7002] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881f06ab790 [ 106.655867][ T7002] RBP: ffff8881d14af860 R08: ffffed103e0d56f3 R09: ffffed103e0d56f3 [ 106.659628][ T7002] R10: 0000000000000001 R11: ffffed103e0d56f2 R12: ffff8881f06ab480 [ 106.663397][ T7002] R13: ffff8881f06ab790 R14: ffff8881df8f6640 R15: ffff8881f06ab748 [ 106.667175][ T7002] FS: 00007f51863e6500(0000) GS:ffff8881f5a00000(0000) knlGS:0000000000000000 [ 106.671480][ T7002] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 106.674937][ T7002] CR2: 00007f5185f0ce70 CR3: 00000001f075d006 CR4: 00000000003606f0 [ 106.678832][ T7002] Call Trace: [ 106.681490][ T7002] ? input_add_uevent_bm_var+0x130/0x130 [ 106.684669][ T7002] dev_uevent+0x330/0x5e0 [ 106.687697][ T7002] ? device_get_devnode+0x2e0/0x2e0 [ 106.690950][ T7002] ? vprintk_func+0x68/0x190 [ 106.693977][ T7002] ? add_uevent_var+0x20c/0x2f0 [ 106.696886][ T7002] ? cleanup_uevent_env+0x50/0x50 [ 106.699818][ T7002] ? kobject_uevent_env+0x347/0x1150 [ 106.702810][ T7002] ? device_get_devnode+0x2e0/0x2e0 [ 106.705952][ T7002] kobject_uevent_env+0x487/0x1150 [ 106.708937][ T7002] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 106.711886][ T7002] kobject_uevent+0x1f/0x30 [ 106.714689][ T7002] kobject_put+0x33c/0x400 [ 106.717543][ T7002] put_device+0x20/0x30 [ 106.720071][ T7002] input_unregister_device+0xba/0xe0 [ 106.723306][ T7002] uinput_destroy_device+0x1e3/0x240 [ 106.726319][ T7002] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 106.729383][ T7002] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 106.732442][ T7002] ? kasan_check_write+0x14/0x20 [ 106.735090][ T7002] ? proc_fail_nth_write+0x94/0x1c0 [ 106.738758][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.741915][ T7002] ? __handle_mm_fault+0x20c0/0x3290 [ 106.744697][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.747313][ T7002] ? __vfs_write+0x111/0x7f0 [ 106.749911][ T7002] uinput_ioctl+0x4c/0x60 [ 106.752365][ T7002] ? uinput_compat_ioctl+0x80/0x80 [ 106.755102][ T7002] do_vfs_ioctl+0x1a9/0x1100 [ 106.757552][ T7002] ? ioctl_preallocate+0x1e0/0x1e0 [ 106.760368][ T7002] ? lock_downgrade+0x880/0x880 [ 106.762722][ T7002] ? check_preemption_disabled+0x3b/0x240 [ 106.765380][ T7002] ? __sb_end_write+0xc6/0x100 [ 106.767791][ T7002] ? vfs_write+0x224/0x4d0 [ 106.769997][ T7002] ? kasan_check_read+0x11/0x20 [ 106.772590][ T7002] ? security_file_ioctl+0x87/0xb0 [ 106.775012][ T7002] ksys_ioctl+0x94/0xb0 [ 106.777240][ T7002] __x64_sys_ioctl+0x73/0xb0 [ 106.779549][ T7002] do_syscall_64+0xe7/0x570 [ 106.781756][ T7002] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 106.784388][ T7002] RIP: 0033:0x7f5185ef6839 [ 106.786485][ T7002] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 106.795212][ T7002] RSP: 002b:00007ffc7a800078 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 106.798602][ T7002] RAX: ffffffffffffffda RBX: 00007ffc7a800080 RCX: 00007f5185ef6839 [ 106.801823][ T7002] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 106.805440][ T7002] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f51861d0038 [ 106.808818][ T7002] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 106.812112][ T7002] R13: 00007ffc7a800190 R14: 0000000000000000 R15: 0000000000000000 [ 106.815416][ T7002] irq event stamp: 2868 [ 106.817657][ T7002] hardirqs last enabled at (2867): [<ffffffff81552310>] console_unlock+0x670/0xd00 [ 106.822995][ T7002] hardirqs last disabled at (2868): [<ffffffff81006087>] trace_hardirqs_off_thunk+0x1a/0x1c [ 106.828472][ T7002] softirqs last enabled at (2864): [<ffffffff86c00673>] __do_softirq+0x673/0x987 [ 106.833767][ T7002] softirqs last disabled at (2855): [<ffffffff8140c0f5>] irq_exit+0x195/0x1c0 [ 106.837681][ T7002] ---[ end trace 781f472231e721f9 ]--- [ 106.841772][ T7002] kobject: 'input22' (00000000e09f1862): calling ktype release [ 106.845524][ T7002] kobject: 'input22': free name ---------------------------------------- From ea8886899e01184801e4c2db2a21892b6006c2c4 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Date: Fri, 25 Jan 2019 14:12:58 +0900 Subject: [PATCH] Input: uinput - Set name/phys to NULL after kfree(). syzbot is hitting use-after-free bug in uinput module [1]. This is because uinput_destroy_device() sometimes kfree()s dev->name and dev->phys at uinput_destroy_device() before dev_uevent() is triggered by dropping the refcount to 0. Since the timing of triggering last input_put_device() is uncontrollable, this patch prepares for such race by setting dev->name and dev->phys to NULL before doing operations which might drop the refcount to 0. [1] https://syzkaller.appspot.com/bug?id=8b17c134fe938bbddd75a45afaa9e68af43a362d Reported-by: syzbot <syzbot+f648cfb7e0b52bf7ae32@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- drivers/input/misc/uinput.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..131591b5babd 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -300,7 +300,9 @@ static void uinput_destroy_device(struct uinput_device *udev) if (dev) { name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in string @ 2019-01-25 9:41 ` Tetsuo Handa 0 siblings, 0 replies; 7+ messages in thread From: Tetsuo Handa @ 2019-01-25 9:41 UTC (permalink / raw) To: dmitry.torokhov, rydberg Cc: syzbot, linux-input, linux-kernel, syzkaller-bugs Hello. syzbot is hitting use-after-free bug in uinput module. It seems that syzbot is hitting this bug from cdev_put() path when closing a character file. But since I can't reproduce the problem, I used a debug patch which raises the refcount as if the character device file is open()ed before uinput_destroy_device() is called. ---------------------------------------- diff --git a/drivers/input/input.c b/drivers/input/input.c index 3304aaaffe87..45fab285f189 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1594,6 +1594,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env) INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name); if (dev->phys) INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys); + WARN_ON(!kref_read(&device->kobj.kref)); if (dev->uniq) INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq); diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..0374ea00d4cc 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -299,8 +299,11 @@ static void uinput_destroy_device(struct uinput_device *udev) udev->state = UIST_NEW_DEVICE; if (dev) { + struct input_dev *d = input_get_device(dev); name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); @@ -310,6 +313,7 @@ static void uinput_destroy_device(struct uinput_device *udev) kfree(name); kfree(phys); udev->dev = NULL; + input_put_device(d); } } ---------------------------------------- I can sometimes observe WARN_ON() because input_put_device() drops the refcount to 0. ---------------------------------------- [ 122.491394][ T7080] kobject: 'input32' (00000000de092799): kobject_add_internal: parent: 'input', set: 'devices' [ 122.497790][ T7080] kobject: 'input32' (00000000de092799): kobject_uevent_env [ 122.501716][ T7080] kobject: 'input32' (00000000de092799): fill_kobj_path: path = '/devices/virtual/input/input32' [ 122.510123][ T7080] kobject: 'input32' (00000000de092799): fill_kobj_path: path = '/devices/virtual/input/input32' [ 122.517230][ T7080] input: syz1 as /devices/virtual/input/input32 [ 122.522334][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_add_internal: parent: 'input32', set: 'devices' [ 122.531090][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_uevent_env [ 122.536589][ T7080] kobject: 'event3' (00000000317a3ed6): fill_kobj_path: path = '/devices/virtual/input/input32/event3' [ 122.545052][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_uevent_env [ 122.549900][ T7080] kobject: 'event3' (00000000317a3ed6): fill_kobj_path: path = '/devices/virtual/input/input32/event3' [ 122.557276][ T7080] FAULT_INJECTION: forcing a failure. [ 122.557276][ T7080] name failslab, interval 1, probability 0, space 0, times 0 [ 122.564580][ T7080] CPU: 0 PID: 7080 Comm: a.out Tainted: G W 5.0.0-rc3+ #142 [ 122.569018][ T7080] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 122.576320][ T7080] Call Trace: [ 122.579087][ T7080] dump_stack+0x154/0x1c5 [ 122.582643][ T7080] should_fail+0x61e/0x720 [ 122.585679][ T7080] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 122.589436][ T7080] ? lock_downgrade+0x880/0x880 [ 122.592499][ T7080] ? ___might_sleep+0x2fe/0x480 [ 122.595518][ T7080] __should_failslab+0xec/0x120 [ 122.598995][ T7080] should_failslab+0x9/0x14 [ 122.601869][ T7080] kmem_cache_alloc+0x47/0x710 [ 122.605051][ T7080] ? refcount_add_not_zero_checked+0x1f0/0x1f0 [ 122.608359][ T7080] ? netlink_broadcast_filtered+0x6c/0xa30 [ 122.611721][ T7080] skb_clone+0x122/0x360 [ 122.614463][ T7080] netlink_broadcast_filtered+0x793/0xa30 [ 122.617568][ T7080] netlink_broadcast+0x3e/0x50 [ 122.620668][ T7080] kobject_uevent_env+0xd51/0x1150 [ 122.623565][ T7080] ? wait_for_completion+0x400/0x400 [ 122.626488][ T7080] kobject_uevent+0x1f/0x30 [ 122.629334][ T7080] device_del+0x673/0xaf0 [ 122.631925][ T7080] ? __device_links_no_driver+0x230/0x230 [ 122.634885][ T7080] ? mark_held_locks+0xaf/0x100 [ 122.637857][ T7080] ? _raw_spin_unlock_irq+0x27/0x80 [ 122.640594][ T7080] ? __input_unregister_device+0x13b/0x480 [ 122.643650][ T7080] ? _raw_spin_unlock_irq+0x27/0x80 [ 122.646334][ T7080] cdev_device_del+0x1a/0x70 [ 122.648825][ T7080] evdev_disconnect+0x42/0xb0 [ 122.651291][ T7080] __input_unregister_device+0x1e3/0x480 [ 122.654279][ T7080] ? kasan_check_read+0x11/0x20 [ 122.656777][ T7080] input_unregister_device+0xa4/0xe0 [ 122.659590][ T7080] uinput_destroy_device+0x216/0x270 [ 122.662130][ T7080] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 122.664850][ T7080] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 122.667560][ T7080] ? kasan_check_write+0x14/0x20 [ 122.670157][ T7080] ? proc_fail_nth_write+0x94/0x1c0 [ 122.672623][ T7080] ? map_files_get_link+0x3c0/0x3c0 [ 122.675253][ T7080] ? __handle_mm_fault+0x20c0/0x3290 [ 122.677842][ T7080] ? map_files_get_link+0x3c0/0x3c0 [ 122.680187][ T7080] ? __vfs_write+0x111/0x7f0 [ 122.682372][ T7080] uinput_ioctl+0x4c/0x60 [ 122.684486][ T7080] ? uinput_compat_ioctl+0x80/0x80 [ 122.687204][ T7080] do_vfs_ioctl+0x1a9/0x1100 [ 122.689530][ T7080] ? ioctl_preallocate+0x1e0/0x1e0 [ 122.691855][ T7080] ? lock_downgrade+0x880/0x880 [ 122.694111][ T7080] ? check_preemption_disabled+0x3b/0x240 [ 122.696603][ T7080] ? __sb_end_write+0xc6/0x100 [ 122.698842][ T7080] ? vfs_write+0x224/0x4d0 [ 122.700991][ T7080] ? kasan_check_read+0x11/0x20 [ 122.703610][ T7080] ? security_file_ioctl+0x87/0xb0 [ 122.706099][ T7080] ksys_ioctl+0x94/0xb0 [ 122.708161][ T7080] __x64_sys_ioctl+0x73/0xb0 [ 122.710525][ T7080] do_syscall_64+0xe7/0x570 [ 122.712669][ T7080] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 122.715185][ T7080] RIP: 0033:0x7f5160b1a839 [ 122.717311][ T7080] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 122.727007][ T7080] RSP: 002b:00007ffe75b27308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 122.731413][ T7080] RAX: ffffffffffffffda RBX: 00007ffe75b27310 RCX: 00007f5160b1a839 [ 122.735723][ T7080] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 122.739593][ T7080] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f5160e00038 [ 122.742850][ T7080] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 122.746101][ T7080] R13: 00007ffe75b27420 R14: 0000000000000000 R15: 0000000000000000 [ 122.750271][ T7080] kobject: '(null)' (00000000eccc95ba): kobject_cleanup, parent 00000000317a3ed6 [ 122.757125][ T7080] kobject: '(null)' (00000000eccc95ba): calling ktype release [ 122.876948][ T7080] kobject: 'event3' (00000000317a3ed6): kobject_cleanup, parent (null) [ 122.882151][ T7080] kobject: 'event3' (00000000317a3ed6): calling ktype release [ 122.885425][ T7080] kobject: 'event3': free name [ 122.888374][ T7080] kobject: 'input32' (00000000de092799): kobject_uevent_env [ 122.891710][ T7080] kobject: 'input32' (00000000de092799): fill_kobj_path: path = '/devices/virtual/input/input32' [ 122.897786][ T7080] kobject: 'input32' (00000000de092799): kobject_cleanup, parent (null) [ 122.903563][ T7080] kobject: 'input32' (00000000de092799): calling ktype release [ 122.907255][ T7080] kobject: 'input32': free name [ 122.923983][ T7085] kobject: 'input33' (000000007fe64e92): kobject_add_internal: parent: 'input', set: 'devices' [ 122.933592][ T7085] kobject: 'input33' (000000007fe64e92): kobject_uevent_env [ 122.939795][ T7085] kobject: 'input33' (000000007fe64e92): fill_kobj_path: path = '/devices/virtual/input/input33' [ 122.946505][ T7085] kobject: 'input33' (000000007fe64e92): fill_kobj_path: path = '/devices/virtual/input/input33' [ 122.956466][ T7085] input: syz1 as /devices/virtual/input/input33 [ 122.961981][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_add_internal: parent: 'input33', set: 'devices' [ 122.970126][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_uevent_env [ 122.974416][ T7085] kobject: 'event3' (000000003c8d2a0d): fill_kobj_path: path = '/devices/virtual/input/input33/event3' [ 122.982226][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_uevent_env [ 122.986290][ T7085] kobject: 'event3' (000000003c8d2a0d): fill_kobj_path: path = '/devices/virtual/input/input33/event3' [ 122.994321][ T7085] kobject: '(null)' (00000000263f9149): kobject_cleanup, parent 000000003c8d2a0d [ 123.001522][ T7085] kobject: '(null)' (00000000263f9149): calling ktype release [ 123.041730][ T7085] kobject: 'event3' (000000003c8d2a0d): kobject_cleanup, parent (null) [ 123.047963][ T7085] kobject: 'event3' (000000003c8d2a0d): calling ktype release [ 123.052144][ T7085] kobject: 'event3': free name [ 123.055887][ T7085] kobject: 'input33' (000000007fe64e92): kobject_uevent_env [ 123.059898][ T7085] FAULT_INJECTION: forcing a failure. [ 123.059898][ T7085] name failslab, interval 1, probability 0, space 0, times 0 [ 123.067534][ T7085] CPU: 2 PID: 7085 Comm: a.out Tainted: G W 5.0.0-rc3+ #142 [ 123.073308][ T7085] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 123.081085][ T7085] Call Trace: [ 123.084204][ T7085] dump_stack+0x154/0x1c5 [ 123.087890][ T7085] should_fail+0x61e/0x720 [ 123.091337][ T7085] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 123.096751][ T7085] ? lock_downgrade+0x880/0x880 [ 123.102104][ T7085] ? ___might_sleep+0x2fe/0x480 [ 123.107205][ T7085] __should_failslab+0xec/0x120 [ 123.112120][ T7085] should_failslab+0x9/0x14 [ 123.116677][ T7085] kmem_cache_alloc_trace+0x4b/0x710 [ 123.121206][ T7085] ? dev_uevent_filter+0xe0/0xe0 [ 123.124370][ T7085] kobject_uevent_env+0x22c/0x1150 [ 123.127605][ T7085] ? wait_for_completion+0x400/0x400 [ 123.130996][ T7085] ? software_node_notify+0xd8/0x2b0 [ 123.134068][ T7085] kobject_uevent+0x1f/0x30 [ 123.137137][ T7085] device_del+0x673/0xaf0 [ 123.140102][ T7085] ? __device_links_no_driver+0x230/0x230 [ 123.143361][ T7085] ? trace_hardirqs_on+0x52/0x1d0 [ 123.146222][ T7085] __input_unregister_device+0x379/0x480 [ 123.149280][ T7085] ? kasan_check_read+0x11/0x20 [ 123.152249][ T7085] input_unregister_device+0xa4/0xe0 [ 123.155458][ T7085] uinput_destroy_device+0x216/0x270 [ 123.158365][ T7085] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 123.161375][ T7085] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 123.164555][ T7085] ? kasan_check_write+0x14/0x20 [ 123.167372][ T7085] ? proc_fail_nth_write+0x94/0x1c0 [ 123.170416][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.174171][ T7085] ? __handle_mm_fault+0x20c0/0x3290 [ 123.177902][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.181524][ T7085] ? __vfs_write+0x111/0x7f0 [ 123.184877][ T7085] uinput_ioctl+0x4c/0x60 [ 123.188445][ T7085] ? uinput_compat_ioctl+0x80/0x80 [ 123.191368][ T7085] do_vfs_ioctl+0x1a9/0x1100 [ 123.193809][ T7085] ? ioctl_preallocate+0x1e0/0x1e0 [ 123.196311][ T7085] ? lock_downgrade+0x880/0x880 [ 123.199013][ T7085] ? check_preemption_disabled+0x3b/0x240 [ 123.201867][ T7085] ? __sb_end_write+0xc6/0x100 [ 123.204412][ T7085] ? vfs_write+0x224/0x4d0 [ 123.206756][ T7085] ? kasan_check_read+0x11/0x20 [ 123.209168][ T7085] ? security_file_ioctl+0x87/0xb0 [ 123.211779][ T7085] ksys_ioctl+0x94/0xb0 [ 123.214142][ T7085] __x64_sys_ioctl+0x73/0xb0 [ 123.216377][ T7085] do_syscall_64+0xe7/0x570 [ 123.218674][ T7085] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 123.221573][ T7085] RIP: 0033:0x7fd9b2d0d839 [ 123.223703][ T7085] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 123.233417][ T7085] RSP: 002b:00007fff66a27408 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 123.237353][ T7085] RAX: ffffffffffffffda RBX: 00007fff66a27410 RCX: 00007fd9b2d0d839 [ 123.241290][ T7085] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 123.246692][ T7085] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007fd9b2ff0038 [ 123.250315][ T7085] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 123.254325][ T7085] R13: 00007fff66a27520 R14: 0000000000000000 R15: 0000000000000000 [ 123.258552][ T7085] kobject: 'input33' (000000007fe64e92): kobject_cleanup, parent (null) [ 123.263643][ T7085] kobject: 'input33' (000000007fe64e92): auto cleanup 'remove' event [ 123.267107][ T7085] kobject: 'input33' (000000007fe64e92): kobject_uevent_env [ 123.270908][ T7085] kobject: 'input33' (000000007fe64e92): fill_kobj_path: path = '/input33' [ 123.274726][ T7085] WARNING: CPU: 2 PID: 7085 at drivers/input/input.c:1597 input_dev_uevent+0x5a2/0x7b0 [ 123.280249][ T7085] Modules linked in: [ 123.282624][ T7085] CPU: 2 PID: 7085 Comm: a.out Tainted: G W 5.0.0-rc3+ #142 [ 123.286383][ T7085] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 123.292981][ T7085] RIP: 0010:input_dev_uevent+0x5a2/0x7b0 [ 123.296185][ T7085] Code: e8 53 5b 25 fd 44 8b 4d d4 e9 03 fb ff ff e8 45 5b 25 fd e9 c2 fa ff ff 4c 89 ef e8 58 5b 25 fd e9 52 fc ff ff e8 6e 62 f3 fc <0f> 0b e9 51 fc ff ff e8 62 62 f3 fc 49 8d 54 24 30 b9 ff 02 00 00 [ 123.306200][ T7085] RSP: 0018:ffff8881e2187830 EFLAGS: 00010293 [ 123.309423][ T7085] RAX: ffff8881de5a6180 RBX: ffff8881df2c6e88 RCX: ffffffff8475e852 [ 123.313674][ T7085] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881df2c6ed0 [ 123.319246][ T7085] RBP: ffff8881e2187868 R08: ffffed103be58ddb R09: ffffed103be58ddb [ 123.324930][ T7085] R10: 0000000000000001 R11: ffffed103be58dda R12: ffff8881df2c6bc0 [ 123.330307][ T7085] R13: ffff8881df2c6ed0 R14: ffff8881dd3a6940 R15: ffff8881df2c6e88 [ 123.334329][ T7085] FS: 00007fd9b31fd500(0000) GS:ffff8881f5a80000(0000) knlGS:0000000000000000 [ 123.338555][ T7085] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 123.342050][ T7085] CR2: 00007fd9b2d9fb24 CR3: 00000001c370e002 CR4: 00000000003606e0 [ 123.345922][ T7085] Call Trace: [ 123.348590][ T7085] ? input_add_uevent_bm_var+0x130/0x130 [ 123.351864][ T7085] dev_uevent+0x330/0x5e0 [ 123.355017][ T7085] ? device_get_devnode+0x2e0/0x2e0 [ 123.358047][ T7085] ? vprintk_func+0x68/0x190 [ 123.360969][ T7085] ? add_uevent_var+0x20c/0x2f0 [ 123.363992][ T7085] ? cleanup_uevent_env+0x50/0x50 [ 123.366933][ T7085] ? kobject_uevent_env+0x347/0x1150 [ 123.370025][ T7085] ? device_get_devnode+0x2e0/0x2e0 [ 123.372997][ T7085] kobject_uevent_env+0x487/0x1150 [ 123.375921][ T7085] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 123.378942][ T7085] kobject_uevent+0x1f/0x30 [ 123.381699][ T7085] kobject_put+0x33c/0x400 [ 123.384375][ T7085] put_device+0x20/0x30 [ 123.387304][ T7085] uinput_destroy_device+0x158/0x270 [ 123.390182][ T7085] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 123.393163][ T7085] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 123.397616][ T7085] ? kasan_check_write+0x14/0x20 [ 123.401440][ T7085] ? proc_fail_nth_write+0x94/0x1c0 [ 123.404393][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.407191][ T7085] ? __handle_mm_fault+0x20c0/0x3290 [ 123.410014][ T7085] ? map_files_get_link+0x3c0/0x3c0 [ 123.412668][ T7085] ? __vfs_write+0x111/0x7f0 [ 123.415202][ T7085] uinput_ioctl+0x4c/0x60 [ 123.417633][ T7085] ? uinput_compat_ioctl+0x80/0x80 [ 123.420355][ T7085] do_vfs_ioctl+0x1a9/0x1100 [ 123.423053][ T7085] ? ioctl_preallocate+0x1e0/0x1e0 [ 123.425574][ T7085] ? lock_downgrade+0x880/0x880 [ 123.427945][ T7085] ? check_preemption_disabled+0x3b/0x240 [ 123.430867][ T7085] ? __sb_end_write+0xc6/0x100 [ 123.433322][ T7085] ? vfs_write+0x224/0x4d0 [ 123.435527][ T7085] ? kasan_check_read+0x11/0x20 [ 123.438404][ T7085] ? security_file_ioctl+0x87/0xb0 [ 123.440847][ T7085] ksys_ioctl+0x94/0xb0 [ 123.442940][ T7085] __x64_sys_ioctl+0x73/0xb0 [ 123.445627][ T7085] do_syscall_64+0xe7/0x570 [ 123.447876][ T7085] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 123.450354][ T7085] RIP: 0033:0x7fd9b2d0d839 [ 123.452589][ T7085] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 123.461381][ T7085] RSP: 002b:00007fff66a27408 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 123.464806][ T7085] RAX: ffffffffffffffda RBX: 00007fff66a27410 RCX: 00007fd9b2d0d839 [ 123.468105][ T7085] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 123.471712][ T7085] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007fd9b2ff0038 [ 123.475028][ T7085] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 123.478476][ T7085] R13: 00007fff66a27520 R14: 0000000000000000 R15: 0000000000000000 [ 123.481837][ T7085] irq event stamp: 2904 [ 123.484128][ T7085] hardirqs last enabled at (2903): [<ffffffff81552310>] console_unlock+0x670/0xd00 [ 123.489864][ T7085] hardirqs last disabled at (2904): [<ffffffff81006087>] trace_hardirqs_off_thunk+0x1a/0x1c [ 123.496220][ T7085] softirqs last enabled at (2888): [<ffffffff86c00673>] __do_softirq+0x673/0x987 [ 123.501609][ T7085] softirqs last disabled at (2869): [<ffffffff8140c0f5>] irq_exit+0x195/0x1c0 [ 123.505845][ T7085] ---[ end trace de7fa7a05c9c270b ]--- [ 123.509700][ T7085] kobject: 'input33' (000000007fe64e92): calling ktype release [ 123.514678][ T7085] kobject: 'input33': free name ---------------------------------------- I also tried reproducing the problem without raising the refcount, ---------------------------------------- diff --git a/drivers/input/input.c b/drivers/input/input.c index 3304aaaffe87..45fab285f189 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1594,6 +1594,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env) INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name); if (dev->phys) INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys); + WARN_ON(!kref_read(&device->kobj.kref)); if (dev->uniq) INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq); diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..131591b5babd 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -300,7 +300,9 @@ static void uinput_destroy_device(struct uinput_device *udev) if (dev) { name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); ---------------------------------------- and I can sometimes observe WARN_ON() because the refcount drops to 0. Therefore, I think that we must not assume that kobject_uevent() won't be called after uinput_destroy_device() called kfree(). ---------------------------------------- [ 96.531017][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_add_internal: parent: 'input', set: 'devices' [ 96.537254][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_uevent_env [ 96.541162][ T6997] kobject: 'input21' (0000000074dfd11f): fill_kobj_path: path = '/devices/virtual/input/input21' [ 96.547745][ T6997] kobject: 'input21' (0000000074dfd11f): fill_kobj_path: path = '/devices/virtual/input/input21' [ 96.554230][ T6997] input: syz1 as /devices/virtual/input/input21 [ 96.559539][ T6997] kobject: 'event3' (00000000648730df): kobject_add_internal: parent: 'input21', set: 'devices' [ 96.569883][ T6997] kobject: 'event3' (00000000648730df): kobject_uevent_env [ 96.574314][ T6997] kobject: 'event3' (00000000648730df): fill_kobj_path: path = '/devices/virtual/input/input21/event3' [ 96.584282][ T6997] kobject: 'event3' (00000000648730df): kobject_uevent_env [ 96.588860][ T6997] kobject: 'event3' (00000000648730df): fill_kobj_path: path = '/devices/virtual/input/input21/event3' [ 96.599355][ T6997] FAULT_INJECTION: forcing a failure. [ 96.599355][ T6997] name failslab, interval 1, probability 0, space 0, times 0 [ 96.607828][ T6997] CPU: 3 PID: 6997 Comm: a.out Not tainted 5.0.0-rc3+ #143 [ 96.611875][ T6997] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 96.619039][ T6997] Call Trace: [ 96.622211][ T6997] dump_stack+0x154/0x1c5 [ 96.625318][ T6997] should_fail+0x61e/0x720 [ 96.628678][ T6997] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 96.632461][ T6997] ? lock_downgrade+0x880/0x880 [ 96.635613][ T6997] ? ___might_sleep+0x2fe/0x480 [ 96.638996][ T6997] __should_failslab+0xec/0x120 [ 96.642133][ T6997] should_failslab+0x9/0x14 [ 96.645003][ T6997] kmem_cache_alloc+0x47/0x710 [ 96.648132][ T6997] ? refcount_add_not_zero_checked+0x1f0/0x1f0 [ 96.651502][ T6997] ? netlink_broadcast_filtered+0x6c/0xa30 [ 96.654754][ T6997] skb_clone+0x122/0x360 [ 96.657877][ T6997] netlink_broadcast_filtered+0x793/0xa30 [ 96.661063][ T6997] netlink_broadcast+0x3e/0x50 [ 96.663850][ T6997] kobject_uevent_env+0xd51/0x1150 [ 96.666808][ T6997] ? wait_for_completion+0x400/0x400 [ 96.669819][ T6997] kobject_uevent+0x1f/0x30 [ 96.672838][ T6997] device_del+0x673/0xaf0 [ 96.675412][ T6997] ? __device_links_no_driver+0x230/0x230 [ 96.678471][ T6997] ? mark_held_locks+0xaf/0x100 [ 96.681207][ T6997] ? _raw_spin_unlock_irq+0x27/0x80 [ 96.683928][ T6997] ? __input_unregister_device+0x13b/0x480 [ 96.686962][ T6997] ? _raw_spin_unlock_irq+0x27/0x80 [ 96.689979][ T6997] cdev_device_del+0x1a/0x70 [ 96.692532][ T6997] evdev_disconnect+0x42/0xb0 [ 96.695109][ T6997] __input_unregister_device+0x1e3/0x480 [ 96.697885][ T6997] ? kasan_check_read+0x11/0x20 [ 96.700421][ T6997] input_unregister_device+0xa4/0xe0 [ 96.702971][ T6997] uinput_destroy_device+0x1e3/0x240 [ 96.705894][ T6997] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 96.708713][ T6997] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 96.711453][ T6997] ? kasan_check_write+0x14/0x20 [ 96.713866][ T6997] ? proc_fail_nth_write+0x94/0x1c0 [ 96.716386][ T6997] ? map_files_get_link+0x3c0/0x3c0 [ 96.718808][ T6997] ? __handle_mm_fault+0x20c0/0x3290 [ 96.721446][ T6997] ? map_files_get_link+0x3c0/0x3c0 [ 96.724169][ T6997] ? __vfs_write+0x111/0x7f0 [ 96.726353][ T6997] uinput_ioctl+0x4c/0x60 [ 96.728983][ T6997] ? uinput_compat_ioctl+0x80/0x80 [ 96.732259][ T6997] do_vfs_ioctl+0x1a9/0x1100 [ 96.735345][ T6997] ? ioctl_preallocate+0x1e0/0x1e0 [ 96.738758][ T6997] ? lock_downgrade+0x880/0x880 [ 96.741859][ T6997] ? check_preemption_disabled+0x3b/0x240 [ 96.744752][ T6997] ? __sb_end_write+0xc6/0x100 [ 96.747207][ T6997] ? vfs_write+0x224/0x4d0 [ 96.750131][ T6997] ? kasan_check_read+0x11/0x20 [ 96.753300][ T6997] ? security_file_ioctl+0x87/0xb0 [ 96.756922][ T6997] ksys_ioctl+0x94/0xb0 [ 96.759615][ T6997] __x64_sys_ioctl+0x73/0xb0 [ 96.761779][ T6997] do_syscall_64+0xe7/0x570 [ 96.764036][ T6997] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 96.766695][ T6997] RIP: 0033:0x7f02ca03a839 [ 96.768823][ T6997] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 96.777498][ T6997] RSP: 002b:00007ffe08c4e418 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 96.780999][ T6997] RAX: ffffffffffffffda RBX: 00007ffe08c4e420 RCX: 00007f02ca03a839 [ 96.784750][ T6997] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 96.788895][ T6997] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f02ca320038 [ 96.792533][ T6997] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 96.796682][ T6997] R13: 00007ffe08c4e530 R14: 0000000000000000 R15: 0000000000000000 [ 96.802099][ T6997] kobject: '(null)' (0000000056da26df): kobject_cleanup, parent 00000000648730df [ 96.808680][ T6997] kobject: '(null)' (0000000056da26df): calling ktype release [ 96.856008][ T6997] kobject: 'event3' (00000000648730df): kobject_cleanup, parent (null) [ 96.863416][ T6997] kobject: 'event3' (00000000648730df): calling ktype release [ 96.868646][ T6997] kobject: 'event3': free name [ 96.871768][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_uevent_env [ 96.876871][ T6997] kobject: 'input21' (0000000074dfd11f): fill_kobj_path: path = '/devices/virtual/input/input21' [ 96.884436][ T6997] kobject: 'input21' (0000000074dfd11f): kobject_cleanup, parent (null) [ 96.891397][ T6997] kobject: 'input21' (0000000074dfd11f): calling ktype release [ 96.896877][ T6997] kobject: 'input21': free name [ 106.244899][ T7002] kobject: 'input22' (00000000e09f1862): kobject_add_internal: parent: 'input', set: 'devices' [ 106.251101][ T7002] kobject: 'input22' (00000000e09f1862): kobject_uevent_env [ 106.255895][ T7002] kobject: 'input22' (00000000e09f1862): fill_kobj_path: path = '/devices/virtual/input/input22' [ 106.262394][ T7002] kobject: 'input22' (00000000e09f1862): fill_kobj_path: path = '/devices/virtual/input/input22' [ 106.269457][ T7002] input: syz1 as /devices/virtual/input/input22 [ 106.273526][ T7002] kobject: 'event3' (000000006eb448c2): kobject_add_internal: parent: 'input22', set: 'devices' [ 106.281027][ T7002] kobject: 'event3' (000000006eb448c2): kobject_uevent_env [ 106.285352][ T7002] kobject: 'event3' (000000006eb448c2): fill_kobj_path: path = '/devices/virtual/input/input22/event3' [ 106.293562][ T7002] kobject: 'event3' (000000006eb448c2): kobject_uevent_env [ 106.297761][ T7002] kobject: 'event3' (000000006eb448c2): fill_kobj_path: path = '/devices/virtual/input/input22/event3' [ 106.305312][ T7002] kobject: '(null)' (00000000192e3ebd): kobject_cleanup, parent 000000006eb448c2 [ 106.314030][ T7002] kobject: '(null)' (00000000192e3ebd): calling ktype release [ 106.404201][ T7002] kobject: 'event3' (000000006eb448c2): kobject_cleanup, parent (null) [ 106.410653][ T7002] kobject: 'event3' (000000006eb448c2): calling ktype release [ 106.414781][ T7002] kobject: 'event3': free name [ 106.418206][ T7002] kobject: 'input22' (00000000e09f1862): kobject_uevent_env [ 106.422387][ T7002] FAULT_INJECTION: forcing a failure. [ 106.422387][ T7002] name failslab, interval 1, probability 0, space 0, times 0 [ 106.429765][ T7002] CPU: 0 PID: 7002 Comm: a.out Not tainted 5.0.0-rc3+ #143 [ 106.433704][ T7002] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 106.440953][ T7002] Call Trace: [ 106.443818][ T7002] dump_stack+0x154/0x1c5 [ 106.446842][ T7002] should_fail+0x61e/0x720 [ 106.449962][ T7002] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 106.453392][ T7002] ? lock_downgrade+0x880/0x880 [ 106.456771][ T7002] ? ___might_sleep+0x2fe/0x480 [ 106.459873][ T7002] __should_failslab+0xec/0x120 [ 106.462960][ T7002] should_failslab+0x9/0x14 [ 106.465843][ T7002] kmem_cache_alloc_trace+0x4b/0x710 [ 106.469001][ T7002] ? dev_uevent_filter+0xe0/0xe0 [ 106.472264][ T7002] kobject_uevent_env+0x22c/0x1150 [ 106.475338][ T7002] ? wait_for_completion+0x400/0x400 [ 106.478399][ T7002] ? software_node_notify+0xd8/0x2b0 [ 106.481321][ T7002] kobject_uevent+0x1f/0x30 [ 106.484081][ T7002] device_del+0x673/0xaf0 [ 106.486758][ T7002] ? __device_links_no_driver+0x230/0x230 [ 106.489994][ T7002] ? trace_hardirqs_on+0x52/0x1d0 [ 106.492762][ T7002] __input_unregister_device+0x379/0x480 [ 106.495713][ T7002] ? kasan_check_read+0x11/0x20 [ 106.498448][ T7002] input_unregister_device+0xa4/0xe0 [ 106.501178][ T7002] uinput_destroy_device+0x1e3/0x240 [ 106.504219][ T7002] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 106.507369][ T7002] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 106.510320][ T7002] ? kasan_check_write+0x14/0x20 [ 106.512855][ T7002] ? proc_fail_nth_write+0x94/0x1c0 [ 106.515504][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.518111][ T7002] ? __handle_mm_fault+0x20c0/0x3290 [ 106.520647][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.523352][ T7002] ? __vfs_write+0x111/0x7f0 [ 106.525728][ T7002] uinput_ioctl+0x4c/0x60 [ 106.527934][ T7002] ? uinput_compat_ioctl+0x80/0x80 [ 106.530418][ T7002] do_vfs_ioctl+0x1a9/0x1100 [ 106.532667][ T7002] ? ioctl_preallocate+0x1e0/0x1e0 [ 106.535138][ T7002] ? lock_downgrade+0x880/0x880 [ 106.537821][ T7002] ? check_preemption_disabled+0x3b/0x240 [ 106.541370][ T7002] ? __sb_end_write+0xc6/0x100 [ 106.544464][ T7002] ? vfs_write+0x224/0x4d0 [ 106.547441][ T7002] ? kasan_check_read+0x11/0x20 [ 106.550570][ T7002] ? security_file_ioctl+0x87/0xb0 [ 106.553765][ T7002] ksys_ioctl+0x94/0xb0 [ 106.556910][ T7002] __x64_sys_ioctl+0x73/0xb0 [ 106.559835][ T7002] do_syscall_64+0xe7/0x570 [ 106.562861][ T7002] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 106.566361][ T7002] RIP: 0033:0x7f5185ef6839 [ 106.569153][ T7002] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 106.577796][ T7002] RSP: 002b:00007ffc7a800078 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 106.581248][ T7002] RAX: ffffffffffffffda RBX: 00007ffc7a800080 RCX: 00007f5185ef6839 [ 106.584590][ T7002] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 106.588145][ T7002] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f51861d0038 [ 106.591466][ T7002] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 106.594767][ T7002] R13: 00007ffc7a800190 R14: 0000000000000000 R15: 0000000000000000 [ 106.598818][ T7002] kobject: 'input22' (00000000e09f1862): kobject_cleanup, parent (null) [ 106.603916][ T7002] kobject: 'input22' (00000000e09f1862): auto cleanup 'remove' event [ 106.607654][ T7002] kobject: 'input22' (00000000e09f1862): kobject_uevent_env [ 106.610810][ T7002] kobject: 'input22' (00000000e09f1862): fill_kobj_path: path = '/input22' [ 106.614563][ T7002] WARNING: CPU: 0 PID: 7002 at drivers/input/input.c:1597 input_dev_uevent+0x5a2/0x7b0 [ 106.619879][ T7002] Modules linked in: [ 106.622530][ T7002] CPU: 0 PID: 7002 Comm: a.out Not tainted 5.0.0-rc3+ #143 [ 106.625853][ T7002] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 [ 106.631813][ T7002] RIP: 0010:input_dev_uevent+0x5a2/0x7b0 [ 106.634771][ T7002] Code: e8 53 5b 25 fd 44 8b 4d d4 e9 03 fb ff ff e8 45 5b 25 fd e9 c2 fa ff ff 4c 89 ef e8 58 5b 25 fd e9 52 fc ff ff e8 6e 62 f3 fc <0f> 0b e9 51 fc ff ff e8 62 62 f3 fc 49 8d 54 24 30 b9 ff 02 00 00 [ 106.644676][ T7002] RSP: 0018:ffff8881d14af828 EFLAGS: 00010293 [ 106.648039][ T7002] RAX: ffff8881d287c300 RBX: ffff8881f06ab748 RCX: ffffffff8475e852 [ 106.651852][ T7002] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881f06ab790 [ 106.655867][ T7002] RBP: ffff8881d14af860 R08: ffffed103e0d56f3 R09: ffffed103e0d56f3 [ 106.659628][ T7002] R10: 0000000000000001 R11: ffffed103e0d56f2 R12: ffff8881f06ab480 [ 106.663397][ T7002] R13: ffff8881f06ab790 R14: ffff8881df8f6640 R15: ffff8881f06ab748 [ 106.667175][ T7002] FS: 00007f51863e6500(0000) GS:ffff8881f5a00000(0000) knlGS:0000000000000000 [ 106.671480][ T7002] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 106.674937][ T7002] CR2: 00007f5185f0ce70 CR3: 00000001f075d006 CR4: 00000000003606f0 [ 106.678832][ T7002] Call Trace: [ 106.681490][ T7002] ? input_add_uevent_bm_var+0x130/0x130 [ 106.684669][ T7002] dev_uevent+0x330/0x5e0 [ 106.687697][ T7002] ? device_get_devnode+0x2e0/0x2e0 [ 106.690950][ T7002] ? vprintk_func+0x68/0x190 [ 106.693977][ T7002] ? add_uevent_var+0x20c/0x2f0 [ 106.696886][ T7002] ? cleanup_uevent_env+0x50/0x50 [ 106.699818][ T7002] ? kobject_uevent_env+0x347/0x1150 [ 106.702810][ T7002] ? device_get_devnode+0x2e0/0x2e0 [ 106.705952][ T7002] kobject_uevent_env+0x487/0x1150 [ 106.708937][ T7002] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 106.711886][ T7002] kobject_uevent+0x1f/0x30 [ 106.714689][ T7002] kobject_put+0x33c/0x400 [ 106.717543][ T7002] put_device+0x20/0x30 [ 106.720071][ T7002] input_unregister_device+0xba/0xe0 [ 106.723306][ T7002] uinput_destroy_device+0x1e3/0x240 [ 106.726319][ T7002] uinput_ioctl_handler.isra.10+0xf63/0x1940 [ 106.729383][ T7002] ? uinput_request_submit.part.9+0x2b0/0x2b0 [ 106.732442][ T7002] ? kasan_check_write+0x14/0x20 [ 106.735090][ T7002] ? proc_fail_nth_write+0x94/0x1c0 [ 106.738758][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.741915][ T7002] ? __handle_mm_fault+0x20c0/0x3290 [ 106.744697][ T7002] ? map_files_get_link+0x3c0/0x3c0 [ 106.747313][ T7002] ? __vfs_write+0x111/0x7f0 [ 106.749911][ T7002] uinput_ioctl+0x4c/0x60 [ 106.752365][ T7002] ? uinput_compat_ioctl+0x80/0x80 [ 106.755102][ T7002] do_vfs_ioctl+0x1a9/0x1100 [ 106.757552][ T7002] ? ioctl_preallocate+0x1e0/0x1e0 [ 106.760368][ T7002] ? lock_downgrade+0x880/0x880 [ 106.762722][ T7002] ? check_preemption_disabled+0x3b/0x240 [ 106.765380][ T7002] ? __sb_end_write+0xc6/0x100 [ 106.767791][ T7002] ? vfs_write+0x224/0x4d0 [ 106.769997][ T7002] ? kasan_check_read+0x11/0x20 [ 106.772590][ T7002] ? security_file_ioctl+0x87/0xb0 [ 106.775012][ T7002] ksys_ioctl+0x94/0xb0 [ 106.777240][ T7002] __x64_sys_ioctl+0x73/0xb0 [ 106.779549][ T7002] do_syscall_64+0xe7/0x570 [ 106.781756][ T7002] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 106.784388][ T7002] RIP: 0033:0x7f5185ef6839 [ 106.786485][ T7002] Code: 00 f3 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 [ 106.795212][ T7002] RSP: 002b:00007ffc7a800078 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 106.798602][ T7002] RAX: ffffffffffffffda RBX: 00007ffc7a800080 RCX: 00007f5185ef6839 [ 106.801823][ T7002] RDX: 0000000000000001 RSI: 0000000000005502 RDI: 0000000000000004 [ 106.805440][ T7002] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f51861d0038 [ 106.808818][ T7002] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 106.812112][ T7002] R13: 00007ffc7a800190 R14: 0000000000000000 R15: 0000000000000000 [ 106.815416][ T7002] irq event stamp: 2868 [ 106.817657][ T7002] hardirqs last enabled at (2867): [<ffffffff81552310>] console_unlock+0x670/0xd00 [ 106.822995][ T7002] hardirqs last disabled at (2868): [<ffffffff81006087>] trace_hardirqs_off_thunk+0x1a/0x1c [ 106.828472][ T7002] softirqs last enabled at (2864): [<ffffffff86c00673>] __do_softirq+0x673/0x987 [ 106.833767][ T7002] softirqs last disabled at (2855): [<ffffffff8140c0f5>] irq_exit+0x195/0x1c0 [ 106.837681][ T7002] ---[ end trace 781f472231e721f9 ]--- [ 106.841772][ T7002] kobject: 'input22' (00000000e09f1862): calling ktype release [ 106.845524][ T7002] kobject: 'input22': free name ---------------------------------------- >From ea8886899e01184801e4c2db2a21892b6006c2c4 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Date: Fri, 25 Jan 2019 14:12:58 +0900 Subject: [PATCH] Input: uinput - Set name/phys to NULL after kfree(). syzbot is hitting use-after-free bug in uinput module [1]. This is because uinput_destroy_device() sometimes kfree()s dev->name and dev->phys at uinput_destroy_device() before dev_uevent() is triggered by dropping the refcount to 0. Since the timing of triggering last input_put_device() is uncontrollable, this patch prepares for such race by setting dev->name and dev->phys to NULL before doing operations which might drop the refcount to 0. [1] https://syzkaller.appspot.com/bug?id=8b17c134fe938bbddd75a45afaa9e68af43a362d Reported-by: syzbot <syzbot+f648cfb7e0b52bf7ae32@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- drivers/input/misc/uinput.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..131591b5babd 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -300,7 +300,9 @@ static void uinput_destroy_device(struct uinput_device *udev) if (dev) { name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH (resend)] Input: uinput - Set name/phys to NULL before kfree(). 2019-01-25 9:41 ` Tetsuo Handa (?) @ 2019-02-08 10:25 ` Tetsuo Handa 2019-02-17 21:07 ` Dmitry Torokhov -1 siblings, 1 reply; 7+ messages in thread From: Tetsuo Handa @ 2019-02-08 10:25 UTC (permalink / raw) To: dmitry.torokhov, rydberg Cc: syzbot, linux-input, linux-kernel, syzkaller-bugs syzbot is hitting use-after-free bug in uinput module [1]. This is because uinput_destroy_device() sometimes kfree()s dev->name and dev->phys at uinput_destroy_device() before dev_uevent() is triggered by dropping the refcount to 0. Since the timing of triggering last input_put_device() is uncontrollable, this patch prepares for such race by setting dev->name and dev->phys to NULL before doing operations which might drop the refcount to 0. [1] https://syzkaller.appspot.com/bug?id=8b17c134fe938bbddd75a45afaa9e68af43a362d Reported-by: syzbot <syzbot+f648cfb7e0b52bf7ae32@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- drivers/input/misc/uinput.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..131591b5babd 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -300,7 +300,9 @@ static void uinput_destroy_device(struct uinput_device *udev) if (dev) { name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH (resend)] Input: uinput - Set name/phys to NULL before kfree(). 2019-02-08 10:25 ` [PATCH (resend)] Input: uinput - Set name/phys to NULL before kfree() Tetsuo Handa @ 2019-02-17 21:07 ` Dmitry Torokhov 2019-02-18 10:10 ` Tetsuo Handa 0 siblings, 1 reply; 7+ messages in thread From: Dmitry Torokhov @ 2019-02-17 21:07 UTC (permalink / raw) To: Tetsuo Handa; +Cc: rydberg, syzbot, linux-input, linux-kernel, syzkaller-bugs Hi Tetsuo, On Fri, Feb 08, 2019 at 07:25:52PM +0900, Tetsuo Handa wrote: > syzbot is hitting use-after-free bug in uinput module [1]. This is because > uinput_destroy_device() sometimes kfree()s dev->name and dev->phys at > uinput_destroy_device() before dev_uevent() is triggered by dropping the > refcount to 0. Since the timing of triggering last input_put_device() is > uncontrollable, this patch prepares for such race by setting dev->name and > dev->phys to NULL before doing operations which might drop the refcount > to 0. > > [1] https://syzkaller.appspot.com/bug?id=8b17c134fe938bbddd75a45afaa9e68af43a362d Sorry it took me so long to sort out the issue and unfortunately I disagree with your analysis. The issue here is not that we do not know when last reference is being dropped (because we expect that KOBJ_REMOVE uevent will be sent out when we call input_unregister_device, which is quite deterministic) but the kobject cleanup logic added in commit 0f4dafc0563c6c49e17fe14b3f5f356e4c4b8806 ("Kobject: auto-cleanup on final unref") coupled with the fault injected by the syzcaller. The commit tries to send final uevent for objects for which "add" uevent has been sent, but not "remove" event. However in uinput (and general input case) we always take care of sending uevent at unregister, and do not expect to have uevent sent out at the final "put" time. I believe the real fix is to have kobj->state_remove_uevent_sent be set to true as soon as we enter kobject_uevent(kobj, KOBJ_REMOVE) so that it is being set even if memory allocation fails. Doing anything else may violate expectations of subsystem owning the kobject. Thanks. -- Dmitry ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH (resend)] Input: uinput - Set name/phys to NULL before kfree(). 2019-02-17 21:07 ` Dmitry Torokhov @ 2019-02-18 10:10 ` Tetsuo Handa 2019-02-19 18:58 ` Dmitry Torokhov 0 siblings, 1 reply; 7+ messages in thread From: Tetsuo Handa @ 2019-02-18 10:10 UTC (permalink / raw) To: Dmitry Torokhov Cc: rydberg, syzbot, linux-input, linux-kernel, syzkaller-bugs Thank you for responding. On 2019/02/18 6:07, Dmitry Torokhov wrote: > The commit tries to send final uevent for objects for which "add" uevent > has been sent, but not "remove" event. However in uinput (and general > input case) we always take care of sending uevent at unregister, and do > not expect to have uevent sent out at the final "put" time. Then, we want to keep dev->name and dev->phys when calling "unregister" time. > > I believe the real fix is to have kobj->state_remove_uevent_sent be set > to true as soon as we enter kobject_uevent(kobj, KOBJ_REMOVE) so that > it is being set even if memory allocation fails. Doing anything else may > violate expectations of subsystem owning the kobject. If we want to keep dev->name and dev->phys when calling "unregister" time, we could do something like below. Does calling kobject_uevent(KOBJ_REMOVE) without dev->name and dev->phys (to some degree) help (compared to not triggering kobject_uevent(KOBJ_REMOVE) at all) ? diff --git a/drivers/input/input.c b/drivers/input/input.c index 3304aaa..da39a23 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1587,6 +1587,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env) { struct input_dev *dev = to_input_dev(device); + rcu_read_lock(); INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x", dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version); @@ -1618,6 +1619,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env) INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX); INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev); + rcu_read_unlock(); return 0; } diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 26ec603f..6689312 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -308,9 +308,12 @@ static void uinput_destroy_device(struct uinput_device *udev) } else { input_free_device(dev); } + dev->name = NULL; + dev->phys = NULL; + udev->dev = NULL; + synchronize_rcu(); kfree(name); kfree(phys); - udev->dev = NULL; } } ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH (resend)] Input: uinput - Set name/phys to NULL before kfree(). 2019-02-18 10:10 ` Tetsuo Handa @ 2019-02-19 18:58 ` Dmitry Torokhov 0 siblings, 0 replies; 7+ messages in thread From: Dmitry Torokhov @ 2019-02-19 18:58 UTC (permalink / raw) To: Tetsuo Handa; +Cc: rydberg, syzbot, linux-input, linux-kernel, syzkaller-bugs On Mon, Feb 18, 2019 at 07:10:23PM +0900, Tetsuo Handa wrote: > Thank you for responding. > > On 2019/02/18 6:07, Dmitry Torokhov wrote: > > The commit tries to send final uevent for objects for which "add" uevent > > has been sent, but not "remove" event. However in uinput (and general > > input case) we always take care of sending uevent at unregister, and do > > not expect to have uevent sent out at the final "put" time. > > Then, we want to keep dev->name and dev->phys when calling "unregister" time. > > > > > I believe the real fix is to have kobj->state_remove_uevent_sent be set > > to true as soon as we enter kobject_uevent(kobj, KOBJ_REMOVE) so that > > it is being set even if memory allocation fails. Doing anything else may > > violate expectations of subsystem owning the kobject. > > If we want to keep dev->name and dev->phys when calling "unregister" time, > we could do something like below. Does calling kobject_uevent(KOBJ_REMOVE) > without dev->name and dev->phys (to some degree) help (compared to not > triggering kobject_uevent(KOBJ_REMOVE) at all) ? We are talking about handling pretty bad failure (I am not sure if these allocations can fail in real life) so not getting KOBJ_REMOVE uevent is not a big deal. Thanks. -- Dmitry ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-02-19 18:59 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-09-03 21:51 KASAN: use-after-free Read in string syzbot 2019-01-25 9:41 ` Tetsuo Handa 2019-01-25 9:41 ` Tetsuo Handa 2019-02-08 10:25 ` [PATCH (resend)] Input: uinput - Set name/phys to NULL before kfree() Tetsuo Handa 2019-02-17 21:07 ` Dmitry Torokhov 2019-02-18 10:10 ` Tetsuo Handa 2019-02-19 18:58 ` Dmitry Torokhov
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