Messages in this thread | | | Date | Sat, 02 Nov 2019 16:32:08 -0700 | Subject | WARNING: suspicious RCU usage in kvm_dev_ioctl | From | syzbot <> |
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Hello,
syzbot found the following crash on:
HEAD commit: 9d234505 Merge tag 'hwmon-for-v5.4-rc6' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16b06934e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=cbbed3e8d4eb64bf dashboard link: https://syzkaller.appspot.com/bug?extid=75475908cd0910f141ee 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+75475908cd0910f141ee@syzkaller.appspotmail.com
============================= WARNING: suspicious RCU usage 5.4.0-rc5+ #0 Not tainted ----------------------------- include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1 no locks held by syz-executor.4/19966.
stack backtrace: CPU: 0 PID: 19966 Comm: syz-executor.4 Not tainted 5.4.0-rc5+ #0 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+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5438 kvm_get_bus include/linux/kvm_host.h:534 [inline] kvm_get_bus include/linux/kvm_host.h:532 [inline] kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:706 [inline] kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3444 [inline] kvm_dev_ioctl+0x100c/0x1610 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3496 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459f49 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2cbb4fbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2cbb4fc6d4 R13: 00000000004c30a8 R14: 00000000004d7018 R15: 00000000ffffffff
============================= WARNING: suspicious RCU usage 5.4.0-rc5+ #0 Not tainted ----------------------------- include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1 no locks held by syz-executor.4/19966.
stack backtrace: CPU: 0 PID: 19966 Comm: syz-executor.4 Not tainted 5.4.0-rc5+ #0 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+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5438 __kvm_memslots include/linux/kvm_host.h:629 [inline] __kvm_memslots include/linux/kvm_host.h:626 [inline] kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:708 [inline] kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3444 [inline] kvm_dev_ioctl+0x116c/0x1610 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3496 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459f49 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2cbb4fbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2cbb4fc6d4 R13: 00000000004c30a8 R14: 00000000004d7018 R15: 00000000ffffffff
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