From nobody Tue Apr 7 03:30:05 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B5FAC433F5 for ; Mon, 10 Oct 2022 04:56:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231232AbiJJE4L (ORCPT ); Mon, 10 Oct 2022 00:56:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231199AbiJJE4E (ORCPT ); Mon, 10 Oct 2022 00:56:04 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CB845208D for ; Sun, 9 Oct 2022 21:56:03 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id b11-20020a170902d50b00b0017828988079so7428173plg.21 for ; Sun, 09 Oct 2022 21:56:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=RxsdOmr/5R6O83izb+Qz14RQm/ox4oRe3Ga9GwIcpbE=; b=FkFgzyPbZsQ7hNEXjbL2xdIOWZkuMKYfOCsz8o7Aqg0eNxiBSOaNoOrR3Qf9uL60wM VTj6P7p0CFzx5wLDB3obZQ+zs+nrxxyBmcvR4DRDn00o63HqdvGDddgCThc2ABO6jHpw cm9uUOYCeB4KowxD+kNC8NY9xxoq25Ui7uTvS4Age3Yh6hkvwWal5xlAgOLCxDVcI4Id h9ltXeJuibrk4rUk6alMBIUx5VxBnrZ6OKB0LXzOyCqqd4IusJvjjf93Z8l+66nNTSjz PHYdAhYsKdcSUKvRSJx0N22y0DlAlXUJT/57ISO/kCHshWkQIpcznUevOsUJJS4GJR+9 I6dQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=RxsdOmr/5R6O83izb+Qz14RQm/ox4oRe3Ga9GwIcpbE=; b=By4NxPsvDRr9IOmHm6p74rkeaj61WzI22AQxfkyEjj5946tqWZyqwcCjJSxA/J+A53 Rlvd0umQuvCtmXf/KmcpaK8lcadhVKjWUmWlW+S4ErizUlhJX3YRROD4CIWBOJ6qOXtf ZeTRbSPTF7RBc9kkoPvPPKX9IoOKuvjQ+BbQl78XA8n0tXDrQ2epA+fZM2V/wpKd52Xc hIC9Km1HrOdUVs4QiMh8lZyvJHncXD5luirnN0fFglNZ02qugoOYRnOJ1KHaZQ38CGya MZnRqJSpRLQRD04MvLcZswxiQZ0L8KpckqHbNdjQAGP2QP6u1maj6GjVrh3CgnSkx+wc bRFg== X-Gm-Message-State: ACrzQf3hDfR+bbtgI8oR0H31A36mzZAtOwdmCDmUv9+900iYyKE8N+Mo Emt+fMEBtDCnOOOfTZyiCsPwHZ6ASKe9 X-Google-Smtp-Source: AMsMyM7IS1QJd/ZymReZAITcO7D6DJHSctw2xXHR0bqcwB2i2Av+jyamUKWzh6rkAS6jB/SEyZwKBlS8xhj8 X-Received: from sgzhang.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3d89]) (user=sgzhang job=sendgmr) by 2002:a17:90a:cd06:b0:203:ae0e:6a21 with SMTP id d6-20020a17090acd0600b00203ae0e6a21mr1584146pju.0.1665377762552; Sun, 09 Oct 2022 21:56:02 -0700 (PDT) Date: Mon, 10 Oct 2022 04:55:49 +0000 In-Reply-To: <20221010045549.2221965-1-sgzhang@google.com> Mime-Version: 1.0 References: <20221010045549.2221965-1-sgzhang@google.com> X-Mailer: git-send-email 2.38.0.rc1.362.ged0d419d3c-goog Message-ID: <20221010045549.2221965-4-sgzhang@google.com> Subject: [PATCH v4 3/3] mtd: mtdoops: panic caused mtdoops to call mtdoops_erase function immediately From: Ray Zhang To: Miquel Raynal , Richard Weinberger , Vignesh Raghavendra Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Ray Zhang Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The panic function disables the local interrupts, preemption, and all other processors. When the invoked mtdoops needs to erase a used page, calling schedule_work() to do it will not work. Instead, just call mtdoops_erase function immediately. Tested: ~# echo c > /proc/sysrq-trigger [ 171.654759] sysrq: Trigger a crash [ 171.658325] Kernel panic - not syncing: sysrq triggered crash ...... [ 172.406423] mtdoops: not ready 34, 35 (erase immediately) [ 172.432285] mtdoops: ready 34, 35 [ 172.435633] Rebooting in 10 seconds.. Signed-off-by: Ray Zhang --- drivers/mtd/mtdoops.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 0226b9e9ea8f..2f11585b5613 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -170,7 +170,7 @@ static void mtdoops_workfunc_erase(struct work_struct *= work) mtdoops_erase(cxt); } =20 -static void mtdoops_inc_counter(struct mtdoops_context *cxt) +static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic) { cxt->nextpage++; if (cxt->nextpage >=3D cxt->oops_pages) @@ -180,12 +180,20 @@ static void mtdoops_inc_counter(struct mtdoops_contex= t *cxt) cxt->nextcount =3D 0; =20 if (page_is_used(cxt, cxt->nextpage)) { - schedule_work(&cxt->work_erase); - return; + pr_debug("not ready %d, %d (erase %s)\n", + cxt->nextpage, cxt->nextcount, + panic ? "immediately" : "scheduled"); + if (panic) { + /* In case of panic, erase immediately */ + mtdoops_erase(cxt); + } else { + /* Otherwise, schedule work to erase it "nicely" */ + schedule_work(&cxt->work_erase); + } + } else { + pr_debug("ready %d, %d (no erase)\n", + cxt->nextpage, cxt->nextcount); } - - pr_debug("ready %d, %d (no erase)\n", - cxt->nextpage, cxt->nextcount); } =20 static void mtdoops_write(struct mtdoops_context *cxt, int panic) @@ -221,7 +229,7 @@ static void mtdoops_write(struct mtdoops_context *cxt, = int panic) mark_page_used(cxt, cxt->nextpage); memset(cxt->oops_buf, 0xff, record_size); =20 - mtdoops_inc_counter(cxt); + mtdoops_inc_counter(cxt, panic); out: clear_bit(0, &cxt->oops_buf_busy); } @@ -286,7 +294,7 @@ static void find_next_position(struct mtdoops_context *= cxt) cxt->nextcount =3D maxcount; } =20 - mtdoops_inc_counter(cxt); + mtdoops_inc_counter(cxt, 0); } =20 static void mtdoops_do_dump(struct kmsg_dumper *dumper, --=20 2.38.0.rc1.362.ged0d419d3c-goog