On 7 October 2026 16:59:36 BST, "Paul E. McKenney" <[email protected]> wrote: >On Wed, Oct 07, 2026 at 03:09:27AM -0400, Mathieu Desnoyers wrote: >> On 2026-10-06 19:40, Paul E. McKenney wrote: >> > Hello! >> > >> > This is all new code, so the bug could be anywhere. So you all need >> > to know. ;-) >> > >> > I got this from the NOPREEMPT variant of hazptr during a nominal >> > "--duration 60" run of torture.sh on x86 with the guest OS split >across >> > two NUMA nodes: >> > >> > [ 137.765104] WARNING: kernel/rcu/hazptrtorture.c:658 at >hazptr_torture_stats_print+0x25b/0x4f0, CPU#1: hazptr_torture_/136 >> > [ 137.768647] Modules linked in: >> > [ 137.768891] CPU: 1 UID: 0 PID: 136 Comm: hazptr_torture_ Not >tainted 7.3.0-rc5-00661-ga1f1e4890d1d-dirty #193 PREEMPTLAZY >> > [ 137.769683] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), >BIOS 1.16.3-6.el9 11/05/2023 >> > [ 137.770319] RIP: 0010:hazptr_torture_stats_print+0x25b/0x4f0 >> > [ 137.770735] Code: 48 83 c4 20 e8 86 44 fe ff 41 83 fd 01 7e 23 48 >c7 c6 6e 85 17 b0 48 c7 c7 db 27 17 b0 e8 6d 44 fe ff f0 ff 05 76 6e 0a 02 >90 <0f> 0b 90 4c 8b 64 24 70 48 c7 c7 73 85 17 b0 e8 51 44 fe ff 48 8b >> > [ 137.772061] RSP: 0018:ffffa738004ffdf0 EFLAGS: 00010202 >> > [ 137.772435] RAX: 0000000000000004 RBX: ffffa738004ffe08 RCX: >0000000000000027 >> > [ 137.772950] RDX: 0000000000000000 RSI: 0000000000000000 RDI: >0000000000000001 >> > [ 137.773455] RBP: ffffa738004ffe60 R08: 4000000000001236 R09: >ffffffffb01727df >> > [ 137.773980] R10: 0000000020212121 R11: 0000000020212121 R12: >0000000000000000 >> > [ 137.774479] R13: 0000000000000002 R14: 000000000002ffd6 R15: >0000000000034f03 >> > [ 137.775000] FS: 0000000000000000(0000) GS:ffff999c2e502000(0000) >knlGS:0000000000000000 >> > [ 137.775578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> > [ 137.776001] CR2: 0000000000000000 CR3: 0000000008830000 CR4: >00000000000006f0 >> > [ 137.776512] Call Trace: >> > [ 137.776700] <TASK> >> > [ 137.776863] ? __pfx_hazptr_torture_stats+0x10/0x10 >> > [ 137.777207] hazptr_torture_stats+0x25/0x70 >> > [ 137.777508] kthread+0xd9/0x110 >> > [ 137.777751] ? __pfx_kthread+0x10/0x10 >> > [ 137.778017] ret_from_fork+0x1bd/0x220 >> > [ 137.778285] ? __pfx_kthread+0x10/0x10 >> > [ 137.778560] ret_from_fork_asm+0x1a/0x30 >> > [ 137.778849] </TASK> >> > [ 137.779007] ---[ end trace 0000000000000000 ]--- >> > >> > I have not yet seen this during a PREEMPT run. Line 658 of >> > hazptrtorture.c is the WARN_ON_ONCE() below: >> > >> > if (i > 1) { >> > pr_cont("%s", "!!! "); >> > atomic_inc(&n_hazptr_torture_error); >> > WARN_ON_ONCE(i > 1); // Too-short grace period >> > } >> > >> > Any thoughts on what might be causing this? >> >> Hi Paul! >> >> Can you share which tree and branch (commit) this is running ? >> >> Does it include my fix from this series ? That would be patch 1 of: >> >> >https://lore.kernel.org/lkml/[email protected]/ > >Ah, no, I somehow got the impression that this series was going to be >updated, so did not apply it. Apologies! > >I will pull these in. > >> Does it run the additional series from Kunwu Chan found at >> >https://lore.kernel.org/lkml/[email protected]/ >? > >No, but if you are good with it I will pull it in. > >May I add your Acked-by or Reviewed-by?
Sorry to impede but I'd be fine with it going in, I'll add my A-B for this: Acked-by: Bradley Morgan <[email protected]> > > Thanx, Paul > >> Thanks, >> >> Mathieu >> >> > >> > For that matter, can anyone else reproduce this? >> > >> > Thanx, Paul >> >> >> -- >> Mathieu Desnoyers >> EfficiOS Inc. >> https://www.efficios.com --- Thanks! "I'm not a very positive person" - Linus torvalds
