From 36f1648644d769c496a8e47e53603e863e358d73 Mon Sep 17 00:00:00 2001 From: Ruoyu Wang Date: Tue, 9 Jun 2026 16:45:27 +0800 Subject: [PATCH] mtd: slram: remove failed entries from the device list register_device() links a new slram_mtdlist entry before allocating all of the state needed by the entry. If a later allocation, memremap(), or mtd_device_register() fails, the partially initialized entry remains on the global list. A later cleanup can then dereference or free invalid state from that failed entry. Unwind the partially initialized entry and clear the list tail on each failure path after the entry has been linked. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Ruoyu Wang Signed-off-by: Miquel Raynal --- drivers/mtd/devices/slram.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/mtd/devices/slram.c b/drivers/mtd/devices/slram.c index 69cb63d99f57..48c2bc6b65ee 100644 --- a/drivers/mtd/devices/slram.c +++ b/drivers/mtd/devices/slram.c @@ -129,6 +129,7 @@ static int slram_write(struct mtd_info *mtd, loff_t to, size_t len, static int register_device(char *name, unsigned long start, unsigned long length) { slram_mtd_list_t **curmtd; + int ret = -ENOMEM; curmtd = &slram_mtdlist; while (*curmtd) { @@ -155,14 +156,15 @@ static int register_device(char *name, unsigned long start, unsigned long length if (!(*curmtd)->mtdinfo) { E("slram: Cannot allocate new MTD device.\n"); - return(-ENOMEM); + goto err_free_list; } if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start = memremap(start, length, MEMREMAP_WB | MEMREMAP_WT | MEMREMAP_WC))) { E("slram: memremap failed\n"); - return -EIO; + ret = -EIO; + goto err_free_priv; } ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end = ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length; @@ -183,10 +185,8 @@ static int register_device(char *name, unsigned long start, unsigned long length if (mtd_device_register((*curmtd)->mtdinfo, NULL, 0)) { E("slram: Failed to register new device\n"); - memunmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start); - kfree((*curmtd)->mtdinfo->priv); - kfree((*curmtd)->mtdinfo); - return(-EAGAIN); + ret = -EAGAIN; + goto err_unmap; } T("slram: Registered device %s from %luKiB to %luKiB\n", name, (start / 1024), ((start + length) / 1024)); @@ -194,6 +194,16 @@ static int register_device(char *name, unsigned long start, unsigned long length ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start, ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end); return(0); + +err_unmap: + memunmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start); +err_free_priv: + kfree((*curmtd)->mtdinfo->priv); +err_free_list: + kfree((*curmtd)->mtdinfo); + kfree(*curmtd); + *curmtd = NULL; + return ret; } static void unregister_devices(void)