On Tue, Apr 30, 2019 at 9:34 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, 30 Apr 2019, syzbot wrote: > > > Hello, > > > > syzbot has tested the proposed patch but the reproducer still triggered > > crash: > > WARNING in sysfs_remove_group > > > > pvrusb2: Attached sub-driver tuner > > pvrusb2: ***WARNING*** pvrusb2 driver initialization failed due to the > > failure of one or more sub-device kernel modules. > > pvrusb2: You need to resolve the failing condition before this driver can > > function. There should be some earlier messages giving more information > > about the problem. > > ------------[ cut here ]------------ > > sysfs group 'power' not found for kobject '0-0044' > > WARNING: CPU: 1 PID: 586 at fs/sysfs/group.c:254 sysfs_remove_group > > fs/sysfs/group.c:254 [inline] > > WARNING: CPU: 1 PID: 586 at fs/sysfs/group.c:254 > > sysfs_remove_group+0x15a/0x1b0 fs/sysfs/group.c:245 > > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 1 PID: 586 Comm: pvrusb2-context Not tainted 5.1.0-rc3-g43151d6-dirty > > #1 > > 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+0xe8/0x16e lib/dump_stack.c:113 > > panic+0x29d/0x5f2 kernel/panic.c:214 > > __warn.cold+0x20/0x48 kernel/panic.c:571 > > report_bug+0x262/0x2a0 lib/bug.c:186 > > fixup_bug arch/x86/kernel/traps.c:179 [inline] > > fixup_bug arch/x86/kernel/traps.c:174 [inline] > > do_error_trap+0x130/0x1f0 arch/x86/kernel/traps.c:272 > > do_invalid_op+0x37/0x40 arch/x86/kernel/traps.c:291 > > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 > > RIP: 0010:sysfs_remove_group fs/sysfs/group.c:254 [inline] > > RIP: 0010:sysfs_remove_group+0x15a/0x1b0 fs/sysfs/group.c:245 > > Code: 48 89 d9 49 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c > > 01 00 75 41 48 8b 33 48 c7 c7 a0 31 7a 8e e8 e6 c2 6e ff <0f> 0b eb 95 e8 > > 0d de d3 ff e9 d2 fe ff ff 48 89 df e8 00 de d3 ff > > RSP: 0018:ffff88809ced7b70 EFLAGS: 00010286 > > RAX: 0000000000000000 RBX: ffffffff8f037e80 RCX: 0000000000000000 > > RDX: 0000000000000000 RSI: ffffffff815b2132 RDI: ffffed10139daf60 > > RBP: 0000000000000000 R08: ffff88809ce96200 R09: ffffed1015a23edb > > R10: ffffed1015a23eda R11: ffff8880ad11f6d7 R12: ffff888218b8e630 > > R13: ffffffff8f038520 R14: 1ffff110139daf97 R15: ffff888218b8e628 > > dpm_sysfs_remove+0xa2/0xc0 drivers/base/power/sysfs.c:737 > > device_del+0x175/0xb90 drivers/base/core.c:2246 > > usb 4-1: new high-speed USB device number 3 using dummy_hcd > > device_unregister+0x27/0xd0 drivers/base/core.c:2301 > > i2c_unregister_device drivers/i2c/i2c-core-base.c:814 [inline] > > __unregister_client drivers/i2c/i2c-core-base.c:1422 [inline] > > __unregister_client+0x7d/0x90 drivers/i2c/i2c-core-base.c:1418 > > device_for_each_child+0x100/0x170 drivers/base/core.c:2401 > > i2c_del_adapter drivers/i2c/i2c-core-base.c:1485 [inline] > > i2c_del_adapter+0x35b/0x640 drivers/i2c/i2c-core-base.c:1447 > > pvr2_i2c_core_done+0x6e/0xbb > > drivers/media/usb/pvrusb2/pvrusb2-i2c-core.c:662 > > pvr2_hdw_destroy+0x17e/0x380 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2669 > > pvr2_context_destroy+0x89/0x240 > > drivers/media/usb/pvrusb2/pvrusb2-context.c:79 > > pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:146 [inline] > > pvr2_context_thread_func+0x65e/0x870 > > drivers/media/usb/pvrusb2/pvrusb2-context.c:167 > > kthread+0x313/0x420 kernel/kthread.c:253 > > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 > > Kernel Offset: disabled > > Rebooting in 86400 seconds.. > > > > > > Tested on: > > > > commit: 43151d6c usb-fuzzer: main usb gadget fuzzer driver > > git tree: https://github.com/google/kasan.git usb-fuzzer > > console output: https://syzkaller.appspot.com/x/log.txt?x=15433634a00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=274aad0cf966c3bc > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > patch: https://syzkaller.appspot.com/x/patch.diff?x=13df3d24a00000 > > It seems pretty clear that this problem is caused by the > pvr2_context_thread trying to unregister the device before the main > probe routine has finished registering it. > > I'm not familiar enough with this driver to want to fix the problem, > however. Someone else who knows the code better should work on it. Yeah, it's a different bug than I intended to fix. I've sent patch for the original issue (using "WARNING:") though. > > Alan Stern >
