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From: Ray Zhang <sgzhang@google.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	Ray Zhang <sgzhang@google.com>
Subject: [PATCH v3 3/3] mtd: mtdoops: panic caused mtdoops to call mtdoops_erase function immediately
Date: Fri,  7 Oct 2022 21:50:27 +0000	[thread overview]
Message-ID: <20221007215027.918507-4-sgzhang@google.com> (raw)
In-Reply-To: <20221007215027.918507-1-sgzhang@google.com>

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 <sgzhang@google.com>
---
 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 eca48dff9b53..eccb7dea892f 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -168,7 +168,7 @@ static void mtdoops_workfunc_erase(struct work_struct *work)
 	mtdoops_erase(cxt);
 }
 
-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 >= cxt->oops_pages)
@@ -178,12 +178,20 @@ static void mtdoops_inc_counter(struct mtdoops_context *cxt)
 		cxt->nextcount = 0;
 
 	if (page_is_used(cxt, cxt->nextpage)) {
-		schedule_work(&cxt->work_erase);
-		return;
+		pr_debug("mtdoops: 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("mtdoops: ready %d, %d (no erase)\n",
+			 cxt->nextpage, cxt->nextcount);
 	}
-
-	pr_debug("mtdoops: ready %d, %d (no erase)\n",
-		 cxt->nextpage, cxt->nextcount);
 }
 
 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
@@ -219,7 +227,7 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 	mark_page_used(cxt, cxt->nextpage);
 	memset(cxt->oops_buf, 0xff, record_size);
 
-	mtdoops_inc_counter(cxt);
+	mtdoops_inc_counter(cxt, panic);
 out:
 	clear_bit(0, &cxt->oops_buf_busy);
 }
@@ -284,7 +292,7 @@ static void find_next_position(struct mtdoops_context *cxt)
 		cxt->nextcount = maxcount;
 	}
 
-	mtdoops_inc_counter(cxt);
+	mtdoops_inc_counter(cxt, 0);
 }
 
 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
-- 
2.38.0.rc1.362.ged0d419d3c-goog


      parent reply	other threads:[~2022-10-07 21:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-07 21:50 [PATCH v3 0/3] mtd: mtdoops: use pr_ functions, add and direct call mtdoops_erase function when panic Ray Zhang
2022-10-07 21:50 ` [PATCH v3 1/3] mtd: mtdoops: change printk() to counterpart pr_ functions Ray Zhang
2022-10-08  7:25   ` Joe Perches
2022-10-09 10:17     ` Miquel Raynal
2022-10-07 21:50 ` [PATCH v3 2/3] mtd: mtdoops: add mtdoops_erase function and move mtdoops_inc_counter to after it Ray Zhang
2022-10-07 21:50 ` Ray Zhang [this message]

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