From f773f0a331d6c41733b17bebbc1b6cae12e016f5 Mon Sep 17 00:00:00 2001 From: ZhaoLong Wang Date: Sat, 4 Mar 2023 09:41:41 +0800 Subject: [PATCH 1/2] ubi: Fix deadlock caused by recursively holding work_sem During the processing of the bgt, if the sync_erase() return -EBUSY or some other error code in __erase_worker(),schedule_erase() called again lead to the down_read(ubi->work_sem) hold twice and may get block by down_write(ubi->work_sem) in ubi_update_fastmap(), which cause deadlock. ubi bgt other task do_work down_read(&ubi->work_sem) ubi_update_fastmap erase_worker # Blocked by down_read __erase_worker down_write(&ubi->work_sem) schedule_erase schedule_ubi_work down_read(&ubi->work_sem) Fix this by changing input parameter @nested of the schedule_erase() to 'true' to avoid recursively acquiring the down_read(&ubi->work_sem). Also, fix the incorrect comment about @nested parameter of the schedule_erase() because when down_write(ubi->work_sem) is held, the @nested is also need be true. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217093 Fixes: 2e8f08deabbc ("ubi: Fix races around ubi_refill_pools()") Signed-off-by: ZhaoLong Wang Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/wl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 40f39e5d6dfc..26a214f016c1 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -575,7 +575,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, * @vol_id: the volume ID that last used this PEB * @lnum: the last used logical eraseblock number for the PEB * @torture: if the physical eraseblock has to be tortured - * @nested: denotes whether the work_sem is already held in read mode + * @nested: denotes whether the work_sem is already held * * This function returns zero in case of success and a %-ENOMEM in case of * failure. @@ -1131,7 +1131,7 @@ static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk) int err1; /* Re-schedule the LEB for erasure */ - err1 = schedule_erase(ubi, e, vol_id, lnum, 0, false); + err1 = schedule_erase(ubi, e, vol_id, lnum, 0, true); if (err1) { spin_lock(&ubi->wl_lock); wl_entry_destroy(ubi, e); From 1e020e1b96afdecd20680b5b5be2a6ffc3d27628 Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Mon, 6 Mar 2023 09:33:08 +0800 Subject: [PATCH 2/2] ubi: Fix failure attaching when vid_hdr offset equals to (sub)page size Following process will make ubi attaching failed since commit 1b42b1a36fc946 ("ubi: ensure that VID header offset ... size"): ID="0xec,0xa1,0x00,0x15" # 128M 128KB 2KB modprobe nandsim id_bytes=$ID flash_eraseall /dev/mtd0 modprobe ubi mtd="0,2048" # set vid_hdr offset as 2048 (one page) (dmesg): ubi0 error: ubi_attach_mtd_dev [ubi]: VID header offset 2048 too large. UBI error: cannot attach mtd0 UBI error: cannot initialize UBI, error -22 Rework original solution, the key point is making sure 'vid_hdr_shift + UBI_VID_HDR_SIZE < ubi->vid_hdr_alsize', so we should check vid_hdr_shift rather not vid_hdr_offset. Then, ubi still support (sub)page aligined VID header offset. Fixes: 1b42b1a36fc946 ("ubi: ensure that VID header offset ... size") Signed-off-by: Zhihao Cheng Tested-by: Nicolas Schichan Tested-by: Miquel Raynal # v5.10, v4.19 Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/build.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c index 0904eb40c95f..ad025b2ee417 100644 --- a/drivers/mtd/ubi/build.c +++ b/drivers/mtd/ubi/build.c @@ -666,12 +666,6 @@ static int io_init(struct ubi_device *ubi, int max_beb_per1024) ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size); ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size); - if (ubi->vid_hdr_offset && ((ubi->vid_hdr_offset + UBI_VID_HDR_SIZE) > - ubi->vid_hdr_alsize)) { - ubi_err(ubi, "VID header offset %d too large.", ubi->vid_hdr_offset); - return -EINVAL; - } - dbg_gen("min_io_size %d", ubi->min_io_size); dbg_gen("max_write_size %d", ubi->max_write_size); dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size); @@ -689,6 +683,21 @@ static int io_init(struct ubi_device *ubi, int max_beb_per1024) ubi->vid_hdr_aloffset; } + /* + * Memory allocation for VID header is ubi->vid_hdr_alsize + * which is described in comments in io.c. + * Make sure VID header shift + UBI_VID_HDR_SIZE not exceeds + * ubi->vid_hdr_alsize, so that all vid header operations + * won't access memory out of bounds. + */ + if ((ubi->vid_hdr_shift + UBI_VID_HDR_SIZE) > ubi->vid_hdr_alsize) { + ubi_err(ubi, "Invalid VID header offset %d, VID header shift(%d)" + " + VID header size(%zu) > VID header aligned size(%d).", + ubi->vid_hdr_offset, ubi->vid_hdr_shift, + UBI_VID_HDR_SIZE, ubi->vid_hdr_alsize); + return -EINVAL; + } + /* Similar for the data offset */ ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE; ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);