From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794061370; b=EaeWiSYqwt9fa265jmAQTsPC2XUU6uGx19bdnj8QIOtYiZ8aiw6NphNzsWskOJcKe/Q2 2k7uvn3dHdBCa6ZKOeTj1PSo2Ah8E22+5rovDiwbsY15LFazPAgAGhPJZfVGOeDfczh3K 9ZLsl+Pw+h6nB7H+9wOG1Ej8YMDELsdueFNRSbzacXxofec2ofCbayB0ac8hqx21vNAGd rOYHjmAehX9O10l9aIIoZ1IIFP6qN7Hxans7wk4JiLbP+9R6KrK5GZBRem9XPpCiLha0k umJiPn9BsmJp8tCaXqpSh+fxjErvVZpZBqdSGUb7/BXYGcI0SmDjJK1qjs5LenXewYA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061370; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=8voPBZPajOHNO50JDGZ0P+ydqsOO/nXT0r+pkeyaeVw=; b=yaUIe0+QR3CUEsbVQVFxr+kFP9AAOMyXmZq9jAf/ODYFFK33d6WwDpEkY4KHZo06lK/F fxWV45xwUP2+e36vvTjKDCRiU3uvq51tBuSzRqvpx0R1qlZlZFBHoypVsNEG0AujyNRgl pZl+4DEf2pHWQlB8Uh1rwc+LsOrvgsTwqw+ywkaTQr1MWXjGgnbIbYTS+aYA2AnQG780B nPxyqe7xDqQM5auNBUkB0pW77slvG5BcpNpMGDoX7Qb47b/qjmOlukIEP5hALouIpUPJE IP1n1E4YEd7wRNKgRXIbjN1QUAuXTsXoIFKQHQhSVpDS1xEEmIvYQ9EeGb+QNxIQ3SA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=X5o8ds1B; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC7C1606A332; Sat, 7 Nov 2026 14:22:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=X5o8ds1B Received: by smtp.kernel.org (Postfix) with ESMTPSA id 162341F008A1; Sat, 7 Nov 2026 14:22:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061369; bh=8voPBZPajOHNO50JDGZ0P+ydqsOO/nXT0r+pkeyaeVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=X5o8ds1Bs7H5Nm2Q1xHp9R4HYTD1RxH5ALimPbttG5KLetvBNuxa0zIv8YsnuZOye +G9Nh81iM9wJ/EeVEMTg6dniQ5FO8ED2HZhzmJSjAfpTlrq2KGObcfa0XdYZ8SCk9y 0ims2BZvv5wi3JGLQwtRGRzJv8r+cXMeNElOW1QE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Breno Leitao , Catalin Marinas , Oleg Nesterov , Davidlohr Bueso , Lance Yang , Qian Cai , SeongJae Park , Andrew Morton , Sasha Levin Subject: [PATCH 6.12 0492/1536] mm/kmemleak: stop the task stack scan early when interrupted Date: Sat, 7 Nov 2026 08:41:48 -0500 Message-ID: <20261107135011.285502975@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao [ Upstream commit eb11f56eeca56069613d00bf623607e305b271d9 ] scan_block() already checks scan_should_stop() for every pointer and bails out of the current block, but the task stack walk cannot tell and keeps issuing a separate scan_should_stop() between every task. Return that status from scan_block() and use it as the task stack loop condition, so the walk stops as soon as a scan is interrupted. Link: https://lore.kernel.org/20260615-kmemleak-stack-resched-v3-2-acecd7d7fd92@debian.org Signed-off-by: Breno Leitao Suggested-by: Catalin Marinas Reviewed-by: Catalin Marinas Reviewed-by: Oleg Nesterov Cc: Davidlohr Bueso Cc: Lance Yang Cc: Qian Cai Cc: SeongJae Park Signed-off-by: Andrew Morton Stable-dep-of: 3541a2b06ecd ("mm/kmemleak: report RCU-tasks quiescent states during the scan") Signed-off-by: Sasha Levin --- mm/kmemleak.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index a54585f0406e6..44a3a95da9963 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1499,22 +1499,25 @@ static int scan_should_stop(void) /* * Scan a memory block (exclusive range) for valid pointers and add those - * found to the gray list. + * found to the gray list. Return non-zero if the scan was interrupted. */ -static void scan_block(void *_start, void *_end, - struct kmemleak_object *scanned) +static int scan_block(void *_start, void *_end, + struct kmemleak_object *scanned) { unsigned long *ptr; unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); unsigned long *end = _end - (BYTES_PER_POINTER - 1); unsigned long flags; + int stop = 0; raw_spin_lock_irqsave(&kmemleak_lock, flags); for (ptr = start; ptr < end; ptr++) { unsigned long pointer; - if (scan_should_stop()) + if (scan_should_stop()) { + stop = 1; break; + } kasan_disable_current(); pointer = *(unsigned long *)kasan_reset_tag((void *)ptr); @@ -1524,6 +1527,8 @@ static void scan_block(void *_start, void *_end, pointer_update_refs(scanned, pointer, OBJECT_PERCPU); } raw_spin_unlock_irqrestore(&kmemleak_lock, flags); + + return stop; } /* @@ -1679,6 +1684,7 @@ static void kmemleak_scan_task_stacks(void) { struct pid *pid; int nr = 1; + int stop = 0; do { struct task_struct *p = NULL; @@ -1697,13 +1703,13 @@ static void kmemleak_scan_task_stacks(void) void *stack = try_get_task_stack(p); if (stack) { - scan_block(stack, stack + THREAD_SIZE, NULL); + stop = scan_block(stack, stack + THREAD_SIZE, NULL); put_task_stack(p); } put_task_struct(p); } cond_resched(); - } while (pid && !scan_should_stop()); + } while (pid && !stop); } /* -- 2.53.0