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McKenney" To: Vlastimil Babka Cc: linux-mm@kvack.org Subject: Possible KCSAN/lockdep issue in -next barns Message-ID: Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Queue-Id: 588FF100004 X-Rspam-User: X-Stat-Signature: 81ojdgiz4mx6orkwwokh1o3a3ndfi4th X-Rspamd-Server: rspam08 X-HE-Tag: 1768974076-964454 X-HE-Meta: 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 8r73TkS4 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello, Vlastimil, On the off-chance that this is useful new news. This happened in rcutorture's TREE04 scenario running with KCSAN and lockdep enabled. Thoughts? Thanx, Paul ------------------------------------------------------------------------ [ 253.872153] ============================= [ 253.872271] [ BUG: Invalid wait context ] [ 253.872271] 6.19.0-rc6-next-20260120 #21508 Not tainted [ 253.875774] ----------------------------- [ 253.877983] migration/1/23 is trying to lock: [ 253.877983] ffff8afd01054e98 (&barn->lock){..-.}-{3:3}, at: barn_get_empty_sheaf+0x1d/0xb0 [ 253.877983] other info that might help us debug this: [ 253.877983] context-{5:5} [ 253.877983] 3 locks held by migration/1/23: [ 253.877983] #0: ffff8afd01fd89a8 (&p->pi_lock){-.-.}-{2:2}, at: __balance_push_cpu_stop+0x3f/0x200 [ 253.877983] #1: ffffffff9f15c5c8 (rcu_read_lock){....}-{1:3}, at: cpuset_cpus_allowed_fallback+0x27/0x250 [ 253.877983] #2: ffff8afd1f470be0 ((local_lock_t *)&pcs->lock){+.+.}-{3:3}, at: __kfree_rcu_sheaf+0x52/0x3d0 [ 253.877983] stack backtrace: [ 253.877983] CPU: 1 UID: 0 PID: 23 Comm: migration/1 Not tainted 6.19.0-rc6-next-20260120 #21508 PREEMPTLAZY [ 253.877983] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 253.877983] Stopper: __balance_push_cpu_stop+0x0/0x200 <- balance_push+0x118/0x170 [ 253.877983] Call Trace: [ 253.877983] [ 253.877983] __dump_stack+0x22/0x30 [ 253.877983] dump_stack_lvl+0x60/0x80 [ 253.877983] dump_stack+0x19/0x24 [ 253.877983] __lock_acquire+0xd3a/0x28e0 [ 253.877983] ? __lock_acquire+0x5a9/0x28e0 [ 253.877983] ? __lock_acquire+0x5a9/0x28e0 [ 253.877983] ? barn_get_empty_sheaf+0x1d/0xb0 [ 253.877983] lock_acquire+0xc3/0x270 [ 253.877983] ? barn_get_empty_sheaf+0x1d/0xb0 [ 253.877983] ? __kfree_rcu_sheaf+0x52/0x3d0 [ 253.877983] _raw_spin_lock_irqsave+0x47/0x70 [ 253.877983] ? barn_get_empty_sheaf+0x1d/0xb0 [ 253.877983] barn_get_empty_sheaf+0x1d/0xb0 [ 253.877983] ? __kfree_rcu_sheaf+0x52/0x3d0 [ 253.877983] __kfree_rcu_sheaf+0x19f/0x3d0 [ 253.877983] kvfree_call_rcu+0xaf/0x390 [ 253.877983] set_cpus_allowed_force+0xc8/0xf0 [ 253.877983] ? cpuset_cpus_allowed_fallback+0x27/0x250 [ 253.877983] cpuset_cpus_allowed_fallback+0x15d/0x250 [ 253.877983] select_fallback_rq+0x1d8/0x250 [ 253.877983] ? __pfx___balance_push_cpu_stop+0x10/0x10 [ 253.877983] __balance_push_cpu_stop+0x4f/0x200 [ 253.877983] cpu_stopper_thread+0x147/0x210 [ 253.877983] ? __pfx_cpu_stopper_thread+0x10/0x10 [ 253.877983] smpboot_thread_fn+0x24c/0x390 [ 253.877983] ? __pfx_smpboot_thread_fn+0x10/0x10 [ 253.877983] kthread+0x1fa/0x230 [ 253.877983] ? __pfx_smpboot_thread_fn+0x10/0x10 [ 253.877983] ? __pfx_kthread+0x10/0x10 [ 253.877983] ret_from_fork+0x157/0x2c0 [ 253.877983] ? __pfx_kthread+0x10/0x10 [ 253.877983] ret_from_fork_asm+0x1a/0x30 [ 253.877983]