Commit 7cc84e0e authored by Ray Zhang's avatar Ray Zhang Committed by Miquel Raynal
Browse files

mtd: mtdoops: panic caused mtdoops to call mtdoops_erase function immediately 



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: default avatarRay Zhang <sgzhang@google.com>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20221010045549.2221965-4-sgzhang@google.com
parent 340193e0

drivers/mtd/mtdoops.c

+16 −8
Original line number Diff line number Diff line
@@ -170,7 +170,7 @@ 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)
@@ -180,13 +180,21 @@ static void mtdoops_inc_counter(struct mtdoops_context *cxt) 
		cxt->nextcount = 0;



	if (page_is_used(cxt, cxt->nextpage)) {

		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);

		return;

		}



	} else {

		pr_debug("ready %d, %d (no erase)\n",

			 cxt->nextpage, cxt->nextcount);

	}

}



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);



	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 = maxcount;

	}



	mtdoops_inc_counter(cxt);

	mtdoops_inc_counter(cxt, 0);

}



static void mtdoops_do_dump(struct kmsg_dumper *dumper,