The patch titled
Subject: zram: don't call idr_remove() from zram_remove()
has been added to the -mm tree. Its filename is
zram-dont-call-idr_remove-from-zram_remove.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/zram-dont-call-idr_remove-from-zram_remove.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/zram-dont-call-idr_remove-from-zram_remove.patch
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------------------------------------------------------
From: "Jerome Marchand" <jmarchan@xxxxxxxxxx>
Subject: zram: don't call idr_remove() from zram_remove()
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.
Signed-off-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.2+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff -puN drivers/block/zram/zram_drv.c~zram-dont-call-idr_remove-from-zram_remove drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-dont-call-idr_remove-from-zram_remove
+++ a/drivers/block/zram/zram_drv.c
@@ -1325,7 +1325,6 @@ 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);
@@ -1367,9 +1366,10 @@ static ssize_t hot_remove_store(struct c
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);
_
Patches currently in -mm which might be from jmarchan@xxxxxxxxxx are
mm-shmem-add-internal-shmem-resident-memory-accounting.patch
mm-procfs-breakdown-rss-for-anon-shmem-and-file-in-proc-pid-status.patch
zram-dont-call-idr_remove-from-zram_remove.patch
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