From c16f39d14a7e0ec59881fbdb22ae494907534384 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Mon, 10 Feb 2020 21:26:34 +0800 Subject: ubi: fastmap: Free unused fastmap anchor peb during detach When CONFIG_MTD_UBI_FASTMAP is enabled, fm_anchor will be assigned a free PEB during ubi_wl_init() or ubi_update_fastmap(). However if fastmap is not used or disabled on the MTD device, ubi_wl_entry related with the PEB will not be freed during detach. So Fix it by freeing the unused fastmap anchor during detach. Fixes: f9c34bb52997 ("ubi: Fix producing anchor PEBs") Reported-by: syzbot+f317896aae32eb281a58@syzkaller.appspotmail.com Reviewed-by: Sascha Hauer Signed-off-by: Hou Tao Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/fastmap-wl.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/mtd/ubi/fastmap-wl.c b/drivers/mtd/ubi/fastmap-wl.c index 426820ab9afe..b486250923c5 100644 --- a/drivers/mtd/ubi/fastmap-wl.c +++ b/drivers/mtd/ubi/fastmap-wl.c @@ -39,6 +39,13 @@ static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root) return victim; } +static inline void return_unused_peb(struct ubi_device *ubi, + struct ubi_wl_entry *e) +{ + wl_tree_add(e, &ubi->free); + ubi->free_count++; +} + /** * return_unused_pool_pebs - returns unused PEB to the free tree. * @ubi: UBI device description object @@ -52,8 +59,7 @@ static void return_unused_pool_pebs(struct ubi_device *ubi, for (i = pool->used; i < pool->size; i++) { e = ubi->lookuptbl[pool->pebs[i]]; - wl_tree_add(e, &ubi->free); - ubi->free_count++; + return_unused_peb(ubi, e); } } @@ -361,6 +367,11 @@ static void ubi_fastmap_close(struct ubi_device *ubi) return_unused_pool_pebs(ubi, &ubi->fm_pool); return_unused_pool_pebs(ubi, &ubi->fm_wl_pool); + if (ubi->fm_anchor) { + return_unused_peb(ubi, ubi->fm_anchor); + ubi->fm_anchor = NULL; + } + if (ubi->fm) { for (i = 0; i < ubi->fm->used_blocks; i++) kfree(ubi->fm->e[i]); -- cgit v1.2.3 From 294a8dbe34d3b2f6e48eb9058ed21d7fe9348b6b Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Mon, 10 Feb 2020 21:26:35 +0800 Subject: ubi: fastmap: Only produce the initial anchor PEB when fastmap is used Don't produce the initial anchor PEB when ubi device is read-only or fastmap is disabled, else the resulting PEB will be unusable to any volume. Signed-off-by: Hou Tao Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/wl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 837d690a8c60..5146cce5fe32 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -1875,7 +1875,8 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) goto out_free; #ifdef CONFIG_MTD_UBI_FASTMAP - ubi_ensure_anchor_pebs(ubi); + if (!ubi->ro_mode && !ubi->fm_disabled) + ubi_ensure_anchor_pebs(ubi); #endif return 0; -- cgit v1.2.3 From 3676f32a98cd6ed4481c21bceb8b4829d4b6d1cf Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Thu, 19 Mar 2020 17:44:35 -0500 Subject: ubi: ubi-media.h: Replace zero-length array with flexible-array member The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/ubi-media.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h index b5fe8f82281b..386db0598e95 100644 --- a/drivers/mtd/ubi/ubi-media.h +++ b/drivers/mtd/ubi/ubi-media.h @@ -498,6 +498,6 @@ struct ubi_fm_volhdr { struct ubi_fm_eba { __be32 magic; __be32 reserved_pebs; - __be32 pnum[0]; + __be32 pnum[]; } __packed; #endif /* !__UBI_MEDIA_H__ */ -- cgit v1.2.3