Noticed this shift-out-of-bounds error in NFS, and also similar messages logged in a few other drivers when running 5.18-rc1. It seems to have regressed in the last ten days because I didn't see it in the same setup when running an earlier version of the rc (about 10 days ago). Any ideas? [Sun Apr 3 22:16:57 2022] UBSAN: shift-out-of-bounds in lib/percpu-refcount.c:140:63 [Sun Apr 3 22:16:57 2022] left shift of negative value -9223372036854775807 [Sun Apr 3 22:16:57 2022] CPU: 7 PID: 10230 Comm: aio-free-ring-w Not tainted 5.18.0-rc1 #1 [Sun Apr 3 22:16:57 2022] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [Sun Apr 3 22:16:57 2022] Call Trace: [Sun Apr 3 22:16:57 2022] <TASK> [Sun Apr 3 22:16:57 2022] dump_stack_lvl+0x55/0x6d [Sun Apr 3 22:16:57 2022] ubsan_epilogue+0x5/0x40 [Sun Apr 3 22:16:57 2022] __ubsan_handle_shift_out_of_bounds+0xfa/0x140 [Sun Apr 3 22:16:57 2022] ? lock_acquire+0x275/0x320 [Sun Apr 3 22:16:57 2022] ? _raw_spin_unlock_irqrestore+0x40/0x60 [Sun Apr 3 22:16:57 2022] ? percpu_ref_exit+0x87/0x90 [Sun Apr 3 22:16:57 2022] percpu_ref_exit+0x87/0x90 [Sun Apr 3 22:16:57 2022] ioctx_alloc+0x500/0x8f0 [Sun Apr 3 22:16:57 2022] __x64_sys_io_setup+0x58/0x240 [Sun Apr 3 22:16:57 2022] do_syscall_64+0x3a/0x80 [Sun Apr 3 22:16:57 2022] entry_SYSCALL_64_after_hwframe+0x44/0xae [Sun Apr 3 22:16:57 2022] RIP: 0033:0x7f0c32c52d6d [Sun Apr 3 22:16:57 2022] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 73 01 c3 48 8b 0d eb 80 0c 00 f7 d8 64 89 01 48 [Sun Apr 3 22:16:57 2022] RSP: 002b:00007fffff3fedc8 EFLAGS: 00000202 ORIG_RAX: 00000000000000ce [Sun Apr 3 22:16:57 2022] RAX: ffffffffffffffda RBX: 0000000000002710 RCX: 00007f0c32c52d6d [Sun Apr 3 22:16:57 2022] RDX: 00007f0c32c52f47 RSI: 00007fffff3fee08 RDI: 0000000000002710 [Sun Apr 3 22:16:57 2022] RBP: 00007f0c32b586c0 R08: 0000000000000000 R09: 00007fffff3fef08 [Sun Apr 3 22:16:57 2022] R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000c [Sun Apr 3 22:16:57 2022] R13: 00007fffff3fee08 R14: 0000000000000000 R15: 0000000000000000 [Sun Apr 3 22:16:57 2022] </TASK> [Sun Apr 3 22:16:57 2022] ================================================================================ [Sun Apr 3 22:16:57 2022] ================================================================================ [Sun Apr 3 22:16:57 2022] UBSAN: shift-out-of-bounds in ./include/linux/nfs_fs.h:606:9 [Sun Apr 3 22:16:57 2022] left shift of 1 by 63 places cannot be represented in type 'long long int' [Sun Apr 3 22:16:57 2022] CPU: 5 PID: 32260 Comm: kworker/u16:3 Not tainted 5.18.0-rc1 #1 [Sun Apr 3 22:16:57 2022] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [Sun Apr 3 22:16:57 2022] Workqueue: rpciod rpc_async_schedule [sunrpc] [Sun Apr 3 22:16:57 2022] Call Trace: [Sun Apr 3 22:16:57 2022] <TASK> [Sun Apr 3 22:16:57 2022] dump_stack_lvl+0x55/0x6d [Sun Apr 3 22:16:57 2022] ubsan_epilogue+0x5/0x40 [Sun Apr 3 22:16:57 2022] __ubsan_handle_shift_out_of_bounds+0xfa/0x140 [Sun Apr 3 22:16:57 2022] ? lock_acquire+0x275/0x320 [Sun Apr 3 22:16:57 2022] ? ww_mutex_trylock+0x2f1/0x370 [Sun Apr 3 22:16:57 2022] ? nfs_writeback_update_inode+0x5f/0xd0 [nfs] [Sun Apr 3 22:16:57 2022] nfs_writeback_update_inode+0x5f/0xd0 [nfs] [Sun Apr 3 22:16:57 2022] ? trace_raw_output_svcsock_new_socket+0xc0/0xc0 [sunrpc] [Sun Apr 3 22:16:57 2022] ? trace_raw_output_svcsock_new_socket+0xc0/0xc0 [sunrpc] [Sun Apr 3 22:16:57 2022] nfs4_write_done_cb+0x61/0x1d0 [nfsv4] [Sun Apr 3 22:16:57 2022] ? trace_raw_output_svcsock_new_socket+0xc0/0xc0 [sunrpc] [Sun Apr 3 22:16:57 2022] ? trace_raw_output_svcsock_new_socket+0xc0/0xc0 [sunrpc] [Sun Apr 3 22:16:57 2022] ? nfs41_sequence_done+0x2c/0x40 [nfsv4] [Sun Apr 3 22:16:57 2022] nfs_writeback_done+0x37/0x210 [nfs] [Sun Apr 3 22:16:57 2022] ? trace_raw_output_svcsock_new_socket+0xc0/0xc0 [sunrpc] [Sun Apr 3 22:16:57 2022] nfs_pgio_result+0x1d/0x60 [nfs] [Sun Apr 3 22:16:57 2022] rpc_exit_task+0x97/0x2b0 [sunrpc] [Sun Apr 3 22:16:57 2022] __rpc_execute+0xc4/0x7d0 [sunrpc] [Sun Apr 3 22:16:57 2022] ? lock_is_held_type+0xea/0x140 [Sun Apr 3 22:16:57 2022] rpc_async_schedule+0x29/0x40 [sunrpc] [Sun Apr 3 22:16:57 2022] process_one_work+0x25b/0x5f0 [Sun Apr 3 22:16:57 2022] worker_thread+0x30/0x360 [Sun Apr 3 22:16:57 2022] ? process_one_work+0x5f0/0x5f0 [Sun Apr 3 22:16:57 2022] kthread+0xe8/0x110 [Sun Apr 3 22:16:57 2022] ? kthread_complete_and_exit+0x20/0x20 [Sun Apr 3 22:16:57 2022] ret_from_fork+0x22/0x30 [Sun Apr 3 22:16:57 2022] </TASK> [Sun Apr 3 22:16:57 2022] ================================================================================ -- Thanks, Steve