From 1a31b20cd81d5cbc7ec6e24cb08066009a1ca32d Mon Sep 17 00:00:00 2001 From: Sebastian Siewior Date: Thu, 26 Nov 2015 21:23:48 +0100 Subject: [PATCH] mtd: ubi: fixup error correction in do_sync_erase() Since fastmap we gained do_sync_erase(). This function can return an error and its error handling isn't obvious. First the memory allocation for struct ubi_work can fail and as such struct ubi_wl_entry is leaked. However if the memory allocation succeeds then the tail function takes care of the struct ubi_wl_entry. A free here could result in a double free. To make the error handling simpler, I split the tail function into one piece which does the work and another which frees the struct ubi_work which is passed as argument. As result do_sync_erase() can keep the struct on stack and we get rid of one error source. Cc: Fixes: 8199b901a ("UBI: Add fastmap support to the WL sub-system") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/wl.c | 52 ++++++++++++++++++++++++-------------------- 1 file changed, 28 insertions(+), 24 deletions(-) diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index eb4489f9082f..f73233fa737c 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -603,6 +603,7 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, return 0; } +static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk); /** * do_sync_erase - run the erase worker synchronously. * @ubi: UBI device description object @@ -615,20 +616,16 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int vol_id, int lnum, int torture) { - struct ubi_work *wl_wrk; + struct ubi_work wl_wrk; dbg_wl("sync erase of PEB %i", e->pnum); - wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS); - if (!wl_wrk) - return -ENOMEM; - - wl_wrk->e = e; - wl_wrk->vol_id = vol_id; - wl_wrk->lnum = lnum; - wl_wrk->torture = torture; + wl_wrk.e = e; + wl_wrk.vol_id = vol_id; + wl_wrk.lnum = lnum; + wl_wrk.torture = torture; - return erase_worker(ubi, wl_wrk, 0); + return __erase_worker(ubi, &wl_wrk); } /** @@ -1014,7 +1011,7 @@ out_unlock: } /** - * erase_worker - physical eraseblock erase worker function. + * __erase_worker - physical eraseblock erase worker function. * @ubi: UBI device description object * @wl_wrk: the work object * @shutdown: non-zero if the worker has to free memory and exit @@ -1025,8 +1022,7 @@ out_unlock: * needed. Returns zero in case of success and a negative error code in case of * failure. */ -static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, - int shutdown) +static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk) { struct ubi_wl_entry *e = wl_wrk->e; int pnum = e->pnum; @@ -1034,21 +1030,11 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, int lnum = wl_wrk->lnum; int err, available_consumed = 0; - if (shutdown) { - dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec); - kfree(wl_wrk); - wl_entry_destroy(ubi, e); - return 0; - } - dbg_wl("erase PEB %d EC %d LEB %d:%d", pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum); err = sync_erase(ubi, e, wl_wrk->torture); if (!err) { - /* Fine, we've erased it successfully */ - kfree(wl_wrk); - spin_lock(&ubi->wl_lock); wl_tree_add(e, &ubi->free); ubi->free_count++; @@ -1066,7 +1052,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, } ubi_err(ubi, "failed to erase PEB %d, error %d", pnum, err); - kfree(wl_wrk); if (err == -EINTR || err == -ENOMEM || err == -EAGAIN || err == -EBUSY) { @@ -1150,6 +1135,25 @@ out_ro: return err; } +static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, + int shutdown) +{ + int ret; + + if (shutdown) { + struct ubi_wl_entry *e = wl_wrk->e; + + dbg_wl("cancel erasure of PEB %d EC %d", e->pnum, e->ec); + kfree(wl_wrk); + wl_entry_destroy(ubi, e); + return 0; + } + + ret = __erase_worker(ubi, wl_wrk); + kfree(wl_wrk); + return ret; +} + /** * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system. * @ubi: UBI device description object -- 2.39.5