[04/48] mtd: tests: stresstest: bail out if device has not enough eraseblocks

From: Greg KH
Date: Mon Jan 16 2012 - 13:58:29 EST


3.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>

commit 2f4478ccff7df845dc9c0f8996a96373122c4417 upstream.

stresstest needs at least two eraseblocks. Bail out gracefully if that
condition is not met. Fixes the following 'division by zero' OOPS:

[ 619.100000] mtd_stresstest: MTD device size 131072, eraseblock size 131072, page size 2048, count of eraseblocks 1, pages per eraseblock 64, OOB size 64
[ 619.120000] mtd_stresstest: scanning for bad eraseblocks
[ 619.120000] mtd_stresstest: scanned 1 eraseblocks, 0 are bad
[ 619.130000] mtd_stresstest: doing operations
[ 619.130000] mtd_stresstest: 0 operations done
[ 619.140000] Division by zero in kernel.
...

caused by

/* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
eb %= (ebcnt - 1);

Signed-off-by: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
drivers/mtd/tests/mtd_stresstest.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/drivers/mtd/tests/mtd_stresstest.c
+++ b/drivers/mtd/tests/mtd_stresstest.c
@@ -277,6 +277,12 @@ static int __init mtd_stresstest_init(vo
(unsigned long long)mtd->size, mtd->erasesize,
pgsize, ebcnt, pgcnt, mtd->oobsize);

+ if (ebcnt < 2) {
+ printk(PRINT_PREF "error: need at least 2 eraseblocks\n");
+ err = -ENOSPC;
+ goto out_put_mtd;
+ }
+
/* Read or write up 2 eraseblocks at a time */
bufsize = mtd->erasesize * 2;

@@ -315,6 +321,7 @@ out:
kfree(bbt);
vfree(writebuf);
vfree(readbuf);
+out_put_mtd:
put_mtd_device(mtd);
if (err)
printk(PRINT_PREF "error %d occurred\n", err);


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