Hello,
Please apply 96017bf90397 ("rcu-tasks: Simplify trc_read_check_handler() atomic operations") to the stable v5.15 stable kernel. It made it in v5.16.
I confirmed the patch fixes the following splat which happens twice on TRACE02:
[ 765.941351] WARNING: CPU: 0 PID: 80 at kernel/rcu/tasks.h:895 trc_read_check_handler+0x61/0xe0 [ 765.949880] Modules linked in: [ 765.953006] CPU: 0 PID: 80 Comm: rcu_torture_rea Not tainted 5.15.86-rc1+ #25 [ 765.959982] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 [ 765.967964] RIP: 0010:trc_read_check_handler+0x61/0xe0 [ 765.973050] Code: 01 00 89 c0 48 03 2c c5 80 f8 a5 ae c6 45 00 00 [..] [ 765.991768] RSP: 0000:ffffa64ac0003fb0 EFLAGS: 00010047 [ 765.997042] RAX: ffffffffad4f8610 RBX: ffffa26b41bd3000 RCX: ffffa26b5f4ac8c0 [ 766.004418] RDX: 0000000000000000 RSI: ffffffffae978121 RDI: ffffa26b41bd3000 [ 766.011502] RBP: ffffa26b41bd6000 R08: ffffa26b41bd3000 R09: 0000000000000000 [ 766.018778] R10: 0000000000000000 R11: ffffa64ac0003ff8 R12: 0000000000000000 [ 766.025943] R13: ffffa26b5f4ac8c0 R14: 0000000000000000 R15: 0000000000000000 [ 766.034383] FS: 0000000000000000(0000) GS:ffffa26b5f400000(0000) knlGS:0000000000000000 [ 766.042925] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 766.048775] CR2: 0000000000000000 CR3: 0000000001924000 CR4: 00000000000006f0 [ 766.055991] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 766.063135] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 766.070711] Call Trace: [ 766.073515] <IRQ> [ 766.075807] flush_smp_call_function_queue+0xec/0x1a0 [ 766.081087] __sysvec_call_function_single+0x3e/0x1d0 [ 766.086466] sysvec_call_function_single+0x89/0xc0 [ 766.091431] </IRQ> [ 766.093713] <TASK> [ 766.095930] asm_sysvec_call_function_single+0x16/0x20
Full kernel logs: http://box.joelfernandes.org:9080/job/rcutorture_stable/job/Linux%20Stable%2...
Cheers,
- Joel