Commit b3143ec6 authored by Jerome Marchand's avatar Jerome Marchand Committed by Greg Kroah-Hartman

zram: don't call idr_remove() from zram_remove()

commit 17ec4cd9 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: default avatarJerome Marchand <jmarchan@redhat.com>
Acked-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5b243a29
...@@ -1324,7 +1324,6 @@ static int zram_remove(struct zram *zram) ...@@ -1324,7 +1324,6 @@ static int zram_remove(struct zram *zram)
pr_info("Removed device: %s\n", zram->disk->disk_name); 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); blk_cleanup_queue(zram->disk->queue);
del_gendisk(zram->disk); del_gendisk(zram->disk);
put_disk(zram->disk); put_disk(zram->disk);
...@@ -1366,10 +1365,12 @@ static ssize_t hot_remove_store(struct class *class, ...@@ -1366,10 +1365,12 @@ static ssize_t hot_remove_store(struct class *class,
mutex_lock(&zram_index_mutex); mutex_lock(&zram_index_mutex);
zram = idr_find(&zram_index_idr, dev_id); zram = idr_find(&zram_index_idr, dev_id);
if (zram) if (zram) {
ret = zram_remove(zram); ret = zram_remove(zram);
else idr_remove(&zram_index_idr, dev_id);
} else {
ret = -ENODEV; ret = -ENODEV;
}
mutex_unlock(&zram_index_mutex); mutex_unlock(&zram_index_mutex);
return ret ? ret : count; return ret ? ret : count;
......
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