3.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
commit 2b86ab9cc29fcd435cde9378c3b9ffe8b5c76128 upstream.
[1] tried to fix invalid memory access on zram->disk but it didn't
fix properly because get_disk failed during module exit path.
Actually, we don't need to reset zram->disk's capacity to zero
in module exit path so that this patch introduces new argument
"reset_capacity" on zram_reset_divice and it only reset it when
reset_store is called.
[1] 6030ea9b, zram: avoid invalid memory access in zram_exit()
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Jiang Liu <jiang.liu@xxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/zram/zram_drv.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -522,7 +522,7 @@ static int zram_bvec_rw(struct zram *zra
return ret;
}
-static void zram_reset_device(struct zram *zram)
+static void zram_reset_device(struct zram *zram, bool reset_capacity)
{
size_t index;
struct zram_meta *meta;
@@ -551,7 +551,8 @@ static void zram_reset_device(struct zra
memset(&zram->stats, 0, sizeof(zram->stats));
zram->disksize = 0;
- set_capacity(zram->disk, 0);
+ if (reset_capacity)
+ set_capacity(zram->disk, 0);
up_write(&zram->init_lock);
}
@@ -635,7 +636,7 @@ static ssize_t reset_store(struct device
if (bdev)
fsync_bdev(bdev);
- zram_reset_device(zram);
+ zram_reset_device(zram, true);
return len;
}
@@ -902,10 +903,12 @@ static void __exit zram_exit(void)
for (i = 0; i < num_devices; i++) {
zram = &zram_devices[i];
- get_disk(zram->disk);
destroy_device(zram);
- zram_reset_device(zram);
- put_disk(zram->disk);
+ /*
+ * Shouldn't access zram->disk after destroy_device
+ * because destroy_device already released zram->disk.
+ */
+ zram_reset_device(zram, false);
}
unregister_blkdev(zram_major, "zram");
--
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