diff options
Diffstat (limited to 'patches/drivers/mtd_blkdevs-add-mtd_table_mutex-lock-back-to-blktran.patch')
| -rw-r--r-- | patches/drivers/mtd_blkdevs-add-mtd_table_mutex-lock-back-to-blktran.patch | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/patches/drivers/mtd_blkdevs-add-mtd_table_mutex-lock-back-to-blktran.patch b/patches/drivers/mtd_blkdevs-add-mtd_table_mutex-lock-back-to-blktran.patch new file mode 100644 index 00000000..6d36effb --- /dev/null +++ b/patches/drivers/mtd_blkdevs-add-mtd_table_mutex-lock-back-to-blktran.patch @@ -0,0 +1,89 @@ +From 30350f237490eb52050647b2a75f6f4e91b2e44d Mon Sep 17 00:00:00 2001 +From: LiweiSong <liwei.song@windriver.com> +Date: Wed, 31 May 2023 17:31:35 +0800 +Subject: [PATCH] mtd_blkdevs: add mtd_table_mutex lock back to blktrans_{open, + release} to avoid race condition + +without lock mtd_table_mutex in blktrans_{open, release}, there will +be a race condition when access devices /dev/mtd1 and /dev/mtdblock1 +at the same time with a high frequency open and close test: + +kernel BUG at drivers/mtd/mtdcore.c:1221! +Internal error: Oops - BUG: 0 1 PREEMPT_RT SMP +CPU: 0 PID: 15349 Comm: mtd-test Not tainted 5.15.52-rt41-yocto-preempt-rt #1 +Hardware name: SoCFPGA Stratix 10 SoCDK (DT) +pstate: 60000005put_mtd_device+0x4c/0x84 +lr : blktrans_release+0xb0/0x120 +Call trace: +__put_mtd_device+0x4c/0x84 +blktrans_release+0xb0/0x120 +blkdev_put+0xd4/0x210 +blkdev_close+0x34/0x50 +__fput+0x8c/0x240 +____fput+0x1c/0x30 +task_work_run+0x98/00t_64_sync_handler+0xa4/0x130 +el0t_64_sync+0x1a0/0x1a4 + +since the original purpose of commit 799ae31c58ae ("mtd_blkdevs: +don't hold del_mtd_blktrans_dev in blktrans_{open, release}") is +to fix a DEADLOCK issue, here convert mutex_lock to mutex_trylock +and return immediately if failed acquire mtd_table_mutex, then +both race condition and DEADLOCK can be avoided. + +Fixes: 799ae31c58ae ("mtd_blkdevs: don't hold del_mtd_blktrans_dev in blktrans_{open, release}") +Signed-off-by: Liwei Song <liwei.song@windriver.com> +Signed-off-by: He Zhe <zhe.he@windriver.com> +Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com> +--- + drivers/mtd/mtd_blkdevs.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c +index 60b222799871..31967ff4b826 100644 +--- a/drivers/mtd/mtd_blkdevs.c ++++ b/drivers/mtd/mtd_blkdevs.c +@@ -189,6 +189,8 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode) + + kref_get(&dev->ref); + ++ if (!mutex_trylock(&mtd_table_mutex)) ++ return ret; + mutex_lock(&dev->lock); + + if (dev->open) +@@ -213,6 +215,7 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode) + unlock: + dev->open++; + mutex_unlock(&dev->lock); ++ mutex_unlock(&mtd_table_mutex); + return ret; + + error_release: +@@ -221,6 +224,7 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode) + error_put: + module_put(dev->tr->owner); + mutex_unlock(&dev->lock); ++ mutex_unlock(&mtd_table_mutex); + blktrans_dev_put(dev); + return ret; + } +@@ -229,6 +233,8 @@ static void blktrans_release(struct gendisk *disk, fmode_t mode) + { + struct mtd_blktrans_dev *dev = disk->private_data; + ++ if (!mutex_trylock(&mtd_table_mutex)) ++ return; + mutex_lock(&dev->lock); + + if (--dev->open) +@@ -243,6 +249,7 @@ static void blktrans_release(struct gendisk *disk, fmode_t mode) + } + unlock: + mutex_unlock(&dev->lock); ++ mutex_unlock(&mtd_table_mutex); + blktrans_dev_put(dev); + } + +-- +2.34.1 + |