From 5580cdae05aefa96deebd7f5ade9d70c92adabd7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?M=C3=A5rten=20Lindahl?= Date: Sat, 7 Sep 2024 21:28:26 +0200 Subject: [PATCH] ubi: wl: Close down wear-leveling before nand is suspended MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If a reboot/shutdown signal with double force (-ff) is triggered when the erase worker or wear-leveling worker function runs we may end up in a race condition since the MTD device gets a reboot notification and suspends the nand flash before the erase or wear-leveling is done. This will reject all accesses to the flash with -EBUSY. Sequence for the erase worker function: systemctl reboot -ff ubi_thread do_work __do_sys_reboot blocking_notifier_call_chain mtd_reboot_notifier nand_shutdown nand_suspend __erase_worker ubi_sync_erase mtd_erase nand_erase_nand # Blocked by suspended chip nand_get_device => EBUSY Similar sequence for the wear-leveling function: systemctl reboot -ff ubi_thread do_work __do_sys_reboot blocking_notifier_call_chain mtd_reboot_notifier nand_shutdown nand_suspend wear_leveling_worker ubi_eba_copy_leb ubi_io_write mtd_write nand_write_oob # Blocked by suspended chip nand_get_device => EBUSY systemd-shutdown[1]: Rebooting. ubi0 error: ubi_io_write: error -16 while writing 2048 bytes to PEB CPU: 1 PID: 82 Comm: ubi_bgt0d Kdump: loaded Tainted: G O (unwind_backtrace) from [<80107b9f>] (show_stack+0xb/0xc) (show_stack) from [<8033641f>] (dump_stack_lvl+0x2b/0x34) (dump_stack_lvl) from [<803b7f3f>] (ubi_io_write+0x3ab/0x4a8) (ubi_io_write) from [<803b817d>] (ubi_io_write_vid_hdr+0x71/0xb4) (ubi_io_write_vid_hdr) from [<803b6971>] (ubi_eba_copy_leb+0x195/0x2f0) (ubi_eba_copy_leb) from [<803b939b>] (wear_leveling_worker+0x2ff/0x738) (wear_leveling_worker) from [<803b86ef>] (do_work+0x5b/0xb0) (do_work) from [<803b9ee1>] (ubi_thread+0xb1/0x11c) (ubi_thread) from [<8012c113>] (kthread+0x11b/0x134) (kthread) from [<80100139>] (ret_from_fork+0x11/0x38) Exception stack(0x80c43fb0 to 0x80c43ff8) ... ubi0 error: ubi_dump_flash: err -16 while reading 2048 bytes from PEB ubi0 error: wear_leveling_worker: error -16 while moving PEB 246 to PEB ubi0 warning: ubi_ro_mode.part.0: switch to read-only mode ... ubi0 error: do_work: work failed with error code -16 ubi0 error: ubi_thread: ubi_bgt0d: work failed with error code -16 ... Kernel panic - not syncing: Software Watchdog Timer expired Add a reboot notification for the ubi/wear-leveling to shutdown any potential flash work actions before the nand is suspended. Signed-off-by: Mårten Lindahl Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/ubi.h | 2 ++ drivers/mtd/ubi/wl.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index c792b9bcab9bc..26cc53ad34ec7 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -549,6 +549,7 @@ struct ubi_debug_info { * @peb_buf: a buffer of PEB size used for different purposes * @buf_mutex: protects @peb_buf * @ckvol_mutex: serializes static volume checking when opening + * @wl_reboot_notifier: close all wear-leveling work before reboot * * @dbg: debugging information for this UBI device */ @@ -651,6 +652,7 @@ struct ubi_device { void *peb_buf; struct mutex buf_mutex; struct mutex ckvol_mutex; + struct notifier_block wl_reboot_notifier; struct ubi_debug_info dbg; }; diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index fbd399cf65033..4f6f339d8fb8a 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -89,6 +89,7 @@ #include #include #include +#include #include "ubi.h" #include "wl.h" @@ -127,6 +128,8 @@ static int self_check_in_wl_tree(const struct ubi_device *ubi, struct ubi_wl_entry *e, struct rb_root *root); static int self_check_in_pq(const struct ubi_device *ubi, struct ubi_wl_entry *e); +static int ubi_wl_reboot_notifier(struct notifier_block *n, + unsigned long state, void *cmd); /** * wl_tree_add - add a wear-leveling entry to a WL RB-tree. @@ -1950,6 +1953,13 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) if (!ubi->ro_mode && !ubi->fm_disabled) ubi_ensure_anchor_pebs(ubi); #endif + + if (!ubi->wl_reboot_notifier.notifier_call) { + ubi->wl_reboot_notifier.notifier_call = ubi_wl_reboot_notifier; + ubi->wl_reboot_notifier.priority = 1; /* Higher than MTD */ + register_reboot_notifier(&ubi->wl_reboot_notifier); + } + return 0; out_free: @@ -1995,6 +2005,17 @@ void ubi_wl_close(struct ubi_device *ubi) kfree(ubi->lookuptbl); } +static int ubi_wl_reboot_notifier(struct notifier_block *n, + unsigned long state, void *cmd) +{ + struct ubi_device *ubi; + + ubi = container_of(n, struct ubi_device, wl_reboot_notifier); + ubi_wl_close(ubi); + + return NOTIFY_DONE; +} + /** * self_check_ec - make sure that the erase counter of a PEB is correct. * @ubi: UBI device description object