Re: WARNING in pvr2_i2c_core_done

syzbot
2020-07-21T11:20:09Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in kernfs_find_ns

pvrusb2: Invalid write control endpoint
pvrusb2: Invalid write control endpoint
pvrusb2: Invalid write control endpoint
pvrusb2: Invalid write control endpoint
pvrusb2: Invalid write control endpoint
pvrusb2: Invalid write control endpoint
general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
CPU: 0 PID: 78 Comm: pvrusb2-context Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kernfs_find_ns+0x31/0x370 fs/kernfs/dir.c:829
Code: 49 89 d6 41 55 41 54 55 48 89 fd 53 48 83 ec 08 e8 f4 61 af ff 48 8d 7d 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 1e 03 00 00 48 8d bd 98 00 00 00 48 8b 5d 70 48
RSP: 0018:ffff8881d4187938 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff863789c0 RCX: ffffffff85a79ba7
RDX: 000000000000000e RSI: ffffffff81901d1c RDI: 0000000000000070
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff873ed1e7
R10: fffffbfff0e7da3c R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff863790e0
FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557f2b45ae48 CR3: 00000001d2762000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kernfs_find_and_get_ns+0x2f/0x60 fs/kernfs/dir.c:906
kernfs_find_and_get include/linux/kernfs.h:548 [inline]
sysfs_unmerge_group+0x5d/0x160 fs/sysfs/group.c:366
dpm_sysfs_remove+0x62/0xb0 drivers/base/power/sysfs.c:790
device_del+0x18b/0xd20 drivers/base/core.c:2834
device_unregister+0x22/0xc0 drivers/base/core.c:2889
i2c_unregister_device include/linux/err.h:41 [inline]
i2c_client_dev_release+0x39/0x50 drivers/i2c/i2c-core-base.c:465
device_release+0x71/0x200 drivers/base/core.c:1559
kobject_cleanup lib/kobject.c:693 [inline]
kobject_release lib/kobject.c:722 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x245/0x540 lib/kobject.c:739
put_device drivers/base/core.c:2779 [inline]
device_unregister+0x34/0xc0 drivers/base/core.c:2890
i2c_unregister_device+0x38/0x40 include/linux/err.h:41
v4l2_i2c_new_subdev_board+0x159/0x2c0 drivers/media/v4l2-core/v4l2-i2c.c:114
v4l2_i2c_new_subdev+0xb8/0xf0 drivers/media/v4l2-core/v4l2-i2c.c:135
pvr2_hdw_load_subdev drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2023 [inline]
pvr2_hdw_load_modules drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2075 [inline]
pvr2_hdw_setup_low drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2156 [inline]
pvr2_hdw_setup drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2262 [inline]
pvr2_hdw_initialize+0xc8d/0x3600 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2339
pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:109 [inline]
pvr2_context_thread_func+0x250/0x850 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
kthread+0x392/0x470 kernel/kthread.c:291
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351
Modules linked in:
---[ end trace 9af941b6bcb04b01 ]---
RIP: 0010:kernfs_find_ns+0x31/0x370 fs/kernfs/dir.c:829
Code: 49 89 d6 41 55 41 54 55 48 89 fd 53 48 83 ec 08 e8 f4 61 af ff 48 8d 7d 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 1e 03 00 00 48 8d bd 98 00 00 00 48 8b 5d 70 48
RSP: 0018:ffff8881d4187938 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff863789c0 RCX: ffffffff85a79ba7
RDX: 000000000000000e RSI: ffffffff81901d1c RDI: 0000000000000070
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff873ed1e7
R10: fffffbfff0e7da3c R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff863790e0
FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557f2b45ae48 CR3: 00000001d2762000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Tested on:

commit: b791d1bd Merge tag 'locking-kcsan-2020-06-11' of git://git..
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=16dfe440900000
kernel config: https://syzkaller.appspot.com/x/.config?x=ccf1899337a6e343
dashboard link: https://syzkaller.appspot.com/bug?extid=e74a998ca8f1df9cc332
compiler: gcc (GCC) 10.1.0-syz 20200507
patch: https://syzkaller.appspot.com/x/patch.diff?x=117e281b100000