This is a note to let you know that I've just added the patch titled
zram: don't call idr_remove() from zram_remove()
to the 4.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
zram-don-t-call-idr_remove-from-zram_remove.patch
and it can be found in the queue-4.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 17ec4cd985780a7e30aa45bb8f272237c12502a4 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <jmarchan@xxxxxxxxxx>
Date: Fri, 15 Jan 2016 16:54:48 -0800
Subject: zram: don't call idr_remove() from zram_remove()
From: Jerome Marchand <jmarchan@xxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxx: fix coding stype, per Sergey]
Signed-off-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1324,7 +1324,6 @@ 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);
@@ -1366,10 +1365,12 @@ 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);
return ret ? ret : count;
Patches currently in stable-queue which might be from jmarchan@xxxxxxxxxx are
queue-4.3/zram-don-t-call-idr_remove-from-zram_remove.patch
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