On Sun, Jul 21, 2024 at 05:53:21AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 51835949dda3 Merge tag 'net-next-6.11' of git://git.kernel.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=150e825e980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=28bac69fa31fbb3a > dashboard link: https://syzkaller.appspot.com/bug?extid=784d0a1246a539975f05 > compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > userspace arch: arm64 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15d4bf4e980000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17a3c349980000 > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-51835949.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/7a3a01db5542/vmlinux-51835949.xz > kernel image: https://storage.googleapis.com/syzbot-assets/14d329019155/Image-51835949.gz.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+784d0a1246a539975f05@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > Voluntary context switch within RCU read-side critical section! > WARNING: CPU: 0 PID: 3460 at kernel/rcu/tree_plugin.h:330 rcu_note_context_switch+0x354/0x49c kernel/rcu/tree_plugin.h:330 Taking a voluntary context switch in an RCU read-side critical section voids your RCU warranty. > Modules linked in: > CPU: 0 PID: 3460 Comm: syz-executor248 Not tainted 6.10.0-syzkaller-04472-g51835949dda3 #0 > Hardware name: linux,dummy-virt (DT) > pstate: 614000c9 (nZCv daIF +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > pc : rcu_note_context_switch+0x354/0x49c kernel/rcu/tree_plugin.h:330 > lr : rcu_note_context_switch+0x354/0x49c kernel/rcu/tree_plugin.h:330 > sp : ffff800089523d30 > x29: ffff800089523d30 x28: f6f0000005d4a480 x27: 0000000000000000 > x26: 0000000000000000 x25: f6f0000005d4a480 x24: ffff800082643318 > x23: 0000000000000000 x22: f6f0000005d4a480 x21: fff000007f8d6240 > x20: ffff80008261e040 x19: fff000007f8d7040 x18: fffffffffffcb658 > x17: fff07ffffd2b9000 x16: ffff800080000000 x15: 0000000000000048 > x14: fffffffffffcb6a0 x13: ffff80008266b0a8 x12: 000000000000088b > x11: 00000000000002d9 x10: ffff80008271f500 x9 : ffff80008266b0a8 > x8 : 00000000ffffdfff x7 : ffff80008271b0a8 x6 : 00000000000002d9 > x5 : fff000007f8cbf48 x4 : 40000000ffffe2d9 x3 : fff07ffffd2b9000 > x2 : 0000000000000000 x1 : 0000000000000000 x0 : f6f0000005d4a480 > Call trace: > rcu_note_context_switch+0x354/0x49c kernel/rcu/tree_plugin.h:330 > __schedule+0xb0/0x850 kernel/sched/core.c:6417 > __schedule_loop kernel/sched/core.c:6606 [inline] > schedule+0x34/0x104 kernel/sched/core.c:6621 > do_notify_resume+0xe4/0x164 arch/arm64/kernel/entry-common.c:136 > exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline] > exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline] > el0_interrupt+0xc4/0xc8 arch/arm64/kernel/entry-common.c:797 > __el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:802 > el0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:807 > el0t_64_irq+0x19c/0x1a0 arch/arm64/kernel/entry.S:599 > ---[ end trace 0000000000000000 ]--- If we are exiting to user mode, my first guess would be that someone did rcu_read_lock() but forgot the matching rcu_read_unlock(). Can this be reproduced using lockdep? That would pinpoint the unmatched rcu_read_lock(). Thanx, Paul > --- > This report 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 issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing. > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
