Re: [syzbot] [pvrusb2?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

syzbot
2023-10-06T12:42:34Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in pvr2_context_set_notify

pvrusb2: Important functionality might not be entirely working.
pvrusb2: Please consider contacting the driver author to help with further stabilization of the driver.
pvrusb2: **********
usb 1-1: USB disconnect, device number 3
pvrusb2: Device being rendered inoperable
==================================================================
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
Read of size 4 at addr ffff88812c3e68d8 by task kworker/0:2/699

CPU: 0 PID: 699 Comm: kworker/0:2 Not tainted 6.6.0-rc4-syzkaller-00064-g1053c4a4b8fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:475
kasan_report+0xda/0x110 mm/kasan/report.c:588
pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
pvr_disconnect+0x80/0xf0 drivers/media/usb/pvrusb2/pvrusb2-main.c:79
usb_unbind_interface+0x1dd/0x8d0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:569 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:561
__device_release_driver drivers/base/dd.c:1272 [inline]
device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1295
bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
device_del+0x39a/0xa50 drivers/base/core.c:3813
usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1416
usb_disconnect+0x2e1/0x890 drivers/usb/core/hub.c:2252
hub_port_connect drivers/usb/core/hub.c:5280 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5580 [inline]
port_event drivers/usb/core/hub.c:5740 [inline]
hub_event+0x1be0/0x4f30 drivers/usb/core/hub.c:5822
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
</TASK>

Allocated by task 699:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0x87/0x90 mm/kasan/common.c:383
kmalloc include/linux/slab.h:599 [inline]
kzalloc include/linux/slab.h:720 [inline]
pvr2_context_create+0x53/0x2a0 drivers/media/usb/pvrusb2/pvrusb2-context.c:207
pvr_probe+0x25/0xe0 drivers/media/usb/pvrusb2/pvrusb2-main.c:54
usb_probe_interface+0x307/0x930 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x234/0xc90 drivers/base/dd.c:658
__driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830
__device_attach_driver+0x1d4/0x300 drivers/base/dd.c:958
bus_for_each_drv+0x157/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x117e/0x1aa0 drivers/base/core.c:3624
usb_set_configuration+0x10cb/0x1c40 drivers/usb/core/message.c:2207
usb_generic_driver_probe+0xca/0x130 drivers/usb/core/generic.c:238
usb_probe_device+0xda/0x2c0 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x234/0xc90 drivers/base/dd.c:658
__driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830
__device_attach_driver+0x1d4/0x300 drivers/base/dd.c:958
bus_for_each_drv+0x157/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x117e/0x1aa0 drivers/base/core.c:3624
usb_new_device+0xd80/0x1960 drivers/usb/core/hub.c:2589
hub_port_connect drivers/usb/core/hub.c:5440 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5580 [inline]
port_event drivers/usb/core/hub.c:5740 [inline]
hub_event+0x2e62/0x4f30 drivers/usb/core/hub.c:5822
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

Freed by task 902:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
____kasan_slab_free mm/kasan/common.c:236 [inline]
____kasan_slab_free+0x13c/0x190 mm/kasan/common.c:200
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1800 [inline]
slab_free_freelist_hook mm/slub.c:1826 [inline]
slab_free mm/slub.c:3809 [inline]
__kmem_cache_free+0xff/0x330 mm/slub.c:3822
pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

The buggy address belongs to the object at ffff88812c3e6800
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 216 bytes inside of
freed 256-byte region [ffff88812c3e6800, ffff88812c3e6900)

The buggy address belongs to the physical page:
page:ffffea0004b0f980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12c3e6
head:ffffea0004b0f980 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x200000000000840(slab|head|node=0|zone=2)
page_type: 0xffffffff()
raw: 0200000000000840 ffff888100041b40 ffffea0004722a80 dead000000000004
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 699, tgid 699 (kworker/0:2), ts 149486728006, free_ts 149464487231
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
prep_new_page mm/page_alloc.c:1543 [inline]
get_page_from_freelist+0x10e1/0x2fd0 mm/page_alloc.c:3170
__alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
alloc_pages+0x1a9/0x270 mm/mempolicy.c:2297
alloc_slab_page mm/slub.c:1870 [inline]
allocate_slab+0x251/0x380 mm/slub.c:2017
new_slab mm/slub.c:2070 [inline]
___slab_alloc+0x8c7/0x1580 mm/slub.c:3223
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
__slab_alloc_node mm/slub.c:3375 [inline]
slab_alloc_node mm/slub.c:3468 [inline]
__kmem_cache_alloc_node+0x12c/0x310 mm/slub.c:3517
kmalloc_trace+0x25/0xe0 mm/slab_common.c:1114
kmalloc include/linux/slab.h:599 [inline]
kzalloc include/linux/slab.h:720 [inline]
pvr2_context_create+0x53/0x2a0 drivers/media/usb/pvrusb2/pvrusb2-context.c:207
pvr_probe+0x25/0xe0 drivers/media/usb/pvrusb2/pvrusb2-main.c:54
usb_probe_interface+0x307/0x930 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x234/0xc90 drivers/base/dd.c:658
__driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830
__device_attach_driver+0x1d4/0x300 drivers/base/dd.c:958
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1136 [inline]
free_unref_page_prepare+0x460/0xa20 mm/page_alloc.c:2312
free_unref_page+0x33/0x2c0 mm/page_alloc.c:2405
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x4a/0x70 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook mm/slab.h:762 [inline]
slab_alloc_node mm/slub.c:3478 [inline]
__kmem_cache_alloc_node+0x190/0x310 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1022 [inline]
__kmalloc+0x4f/0x100 mm/slab_common.c:1036
kmalloc include/linux/slab.h:603 [inline]
tomoyo_realpath_from_path+0xb9/0x710 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_number_perm+0x241/0x580 security/tomoyo/file.c:723
security_file_ioctl+0x72/0xb0 security/security.c:2647
__do_sys_ioctl fs/ioctl.c:865 [inline]
__se_sys_ioctl fs/ioctl.c:857 [inline]
__x64_sys_ioctl+0xbb/0x210 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff88812c3e6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88812c3e6800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88812c3e6880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88812c3e6900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88812c3e6980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Tested on:

commit: 1053c4a4 Revert "usb: gadget: uvc: stop pump thread on..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1472423a680000
kernel config: https://syzkaller.appspot.com/x/.config?x=a5e01246f94ceed9
dashboard link: https://syzkaller.appspot.com/bug?extid=621409285c4156a009b3
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.