| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 142/268] zram: don't call idr_remove() from zram_remove() | Date | Wed, 27 Jan 2016 12:33:23 -0800 |
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4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know.
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From: Jerome Marchand <jmarchan@redhat.com>
commit 17ec4cd985780a7e30aa45bb8f272237c12502a4 upstream.
The use of idr_remove() is forbidden in the callback functions of idr_for_each(). It is therefore unsafe to call idr_remove in zram_remove().
This patch moves the call to idr_remove() from zram_remove() to hot_remove_store(). In the detroy_devices() path, idrs are removed by idr_destroy(). This solves an use-after-free detected by KASan.
[akpm@linux-foundation.org: fix coding stype, per Sergey] Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/block/zram/zram_drv.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 763301c..6a706f5 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1319,7 +1319,6 @@ static int zram_remove(struct zram *zram) pr_info("Removed device: %s\n", zram->disk->disk_name); - idr_remove(&zram_index_idr, zram->disk->first_minor); blk_cleanup_queue(zram->disk->queue); del_gendisk(zram->disk); put_disk(zram->disk); @@ -1361,10 +1360,12 @@ static ssize_t hot_remove_store(struct class *class, mutex_lock(&zram_index_mutex); zram = idr_find(&zram_index_idr, dev_id); - if (zram) + if (zram) { ret = zram_remove(zram); - else + idr_remove(&zram_index_idr, dev_id); + } else { ret = -ENODEV; + } mutex_unlock(&zram_index_mutex); return ret ? ret : count; -- 1.9.1
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