On Sat, Mar 21, 2020 at 8:12 AM syzbot <syzbot+c07afbbb410e9f712273@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: fb33c651 Linux 5.6-rc6 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=140688d3e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9f894bd92023de02 > dashboard link: https://syzkaller.appspot.com/bug?extid=c07afbbb410e9f712273 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+c07afbbb410e9f712273@xxxxxxxxxxxxxxxxxxxxxxxxx +ashmem maintainers >From the log, ashmem spews an infinite sequence of some errors which probably stall the machine: [ 1094.685541][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641097791 [ 1094.701750][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641383141 [ 1094.708003][ T9576] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641233534 [ 1094.723597][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641083174 [ 1094.730025][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641098111 [ 1094.745592][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641383221 [ 1094.753153][ T9576] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641233534 [ 1094.767903][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641084454 [ 1094.819845][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641526579 [ 1094.830116][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641098111 [ 1094.845813][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641527219 [ 1094.852188][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641098751 [ 1094.871456][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641527219 [ 1094.874256][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641098751 [ 1094.890195][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641528499 [ 1094.895999][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641087014 [ 1094.912931][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641528499 [ 1094.918797][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641100031 [ 1094.936636][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641531059 [ 1094.941391][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641081897 [ 1094.957463][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641531059 [ 1094.963568][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641100031 [ 1094.980233][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641536179 [ 1094.985311][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641081899 [ 1095.001393][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641536179 [ 1095.008146][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641102591 [ 1095.024425][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641525942 [ 1095.029644][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641081904 [ 1095.046399][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641525942 [ 1095.052377][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641102591 [ 1095.068000][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641525944 [ 1095.073934][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641081914 [ 1095.091076][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641525944 [ 1095.096925][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641107711 [ 1095.112305][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641525949 [ 1095.118570][ T1876] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641081934 [ 1095.135413][ T7239] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641525949 [ 1095.141206][ T9460] vmscan: shrink_slab: ashmem_shrink_scan+0x0/0x500 negative objects to delete nr=-6917529027641107711 > INFO: task syz-executor.4:7237 blocked for more than 143 seconds. > Not tainted 5.6.0-rc6-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor.4 D26576 7237 9609 0x00004004 > Call Trace: > schedule+0xd0/0x2a0 kernel/sched/core.c:4154 > schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4213 > __mutex_lock_common kernel/locking/mutex.c:1033 [inline] > __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 > blk_trace_remove+0x1e/0x40 kernel/trace/blktrace.c:361 > sg_ioctl_common+0x221/0x2710 drivers/scsi/sg.c:1125 > sg_ioctl+0x8f/0x120 drivers/scsi/sg.c:1159 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 > __do_sys_ioctl fs/ioctl.c:772 [inline] > __se_sys_ioctl fs/ioctl.c:770 [inline] > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 > do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45c849 > Code: Bad RIP value. > RSP: 002b:00007f5ba5a3bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f5ba5a3c6d4 RCX: 000000000045c849 > RDX: 0000000000000000 RSI: 0000000000001276 RDI: 0000000000000003 > RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 000000000000022b R14: 00000000004c4526 R15: 000000000076bf0c > INFO: task syz-executor.4:7266 blocked for more than 146 seconds. > Not tainted 5.6.0-rc6-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor.4 D27752 7266 9609 0x00004004 > Call Trace: > schedule+0xd0/0x2a0 kernel/sched/core.c:4154 > schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4213 > __mutex_lock_common kernel/locking/mutex.c:1033 [inline] > __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 > blk_trace_setup+0x2f/0x60 kernel/trace/blktrace.c:588 > sg_ioctl_common+0x2f2/0x2710 drivers/scsi/sg.c:1116 > sg_ioctl+0x8f/0x120 drivers/scsi/sg.c:1159 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 > __do_sys_ioctl fs/ioctl.c:772 [inline] > __se_sys_ioctl fs/ioctl.c:770 [inline] > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 > do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45c849 > Code: Bad RIP value. > RSP: 002b:00007f5ba5a1ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f5ba5a1b6d4 RCX: 000000000045c849 > RDX: 0000000020000080 RSI: 00000000c0481273 RDI: 0000000000000008 > RBP: 000000000076bfa0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 0000000000000228 R14: 00000000004c44eb R15: 000000000076bfac > INFO: task syz-executor.5:7265 blocked for more than 149 seconds. > Not tainted 5.6.0-rc6-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor.5 D26736 7265 9613 0x00004004 > Call Trace: > schedule+0xd0/0x2a0 kernel/sched/core.c:4154 > schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4213 > __mutex_lock_common kernel/locking/mutex.c:1033 [inline] > __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 > blk_trace_setup+0x2f/0x60 kernel/trace/blktrace.c:588 > sg_ioctl_common+0x2f2/0x2710 drivers/scsi/sg.c:1116 > sg_ioctl+0x8f/0x120 drivers/scsi/sg.c:1159 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 > __do_sys_ioctl fs/ioctl.c:772 [inline] > __se_sys_ioctl fs/ioctl.c:770 [inline] > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 > do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45c849 > Code: Bad RIP value. > RSP: 002b:00007f576f48ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f576f48b6d4 RCX: 000000000045c849 > RDX: 0000000020000080 RSI: 00000000c0481273 RDI: 0000000000000006 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/0000000000000bec9805a1581f05%40google.com.
