From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/mtd/ubi/misc.c | 191 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 191 insertions(+) create mode 100644 drivers/mtd/ubi/misc.c (limited to 'drivers/mtd/ubi/misc.c') diff --git a/drivers/mtd/ubi/misc.c b/drivers/mtd/ubi/misc.c new file mode 100644 index 000000000..1794d66b6 --- /dev/null +++ b/drivers/mtd/ubi/misc.c @@ -0,0 +1,191 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) International Business Machines Corp., 2006 + * + * Author: Artem Bityutskiy (Битюцкий Артём) + */ + +/* Here we keep miscellaneous functions which are used all over the UBI code */ + +#include "ubi.h" + +/** + * ubi_calc_data_len - calculate how much real data is stored in a buffer. + * @ubi: UBI device description object + * @buf: a buffer with the contents of the physical eraseblock + * @length: the buffer length + * + * This function calculates how much "real data" is stored in @buf and returnes + * the length. Continuous 0xFF bytes at the end of the buffer are not + * considered as "real data". + */ +int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, + int length) +{ + int i; + + ubi_assert(!(length & (ubi->min_io_size - 1))); + + for (i = length - 1; i >= 0; i--) + if (((const uint8_t *)buf)[i] != 0xFF) + break; + + /* The resulting length must be aligned to the minimum flash I/O size */ + length = ALIGN(i + 1, ubi->min_io_size); + return length; +} + +/** + * ubi_check_volume - check the contents of a static volume. + * @ubi: UBI device description object + * @vol_id: ID of the volume to check + * + * This function checks if static volume @vol_id is corrupted by fully reading + * it and checking data CRC. This function returns %0 if the volume is not + * corrupted, %1 if it is corrupted and a negative error code in case of + * failure. Dynamic volumes are not checked and zero is returned immediately. + */ +int ubi_check_volume(struct ubi_device *ubi, int vol_id) +{ + void *buf; + int err = 0, i; + struct ubi_volume *vol = ubi->volumes[vol_id]; + + if (vol->vol_type != UBI_STATIC_VOLUME) + return 0; + + buf = vmalloc(vol->usable_leb_size); + if (!buf) + return -ENOMEM; + + for (i = 0; i < vol->used_ebs; i++) { + int size; + + cond_resched(); + + if (i == vol->used_ebs - 1) + size = vol->last_eb_bytes; + else + size = vol->usable_leb_size; + + err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1); + if (err) { + if (mtd_is_eccerr(err)) + err = 1; + break; + } + } + + vfree(buf); + return err; +} + +/** + * ubi_update_reserved - update bad eraseblock handling accounting data. + * @ubi: UBI device description object + * + * This function calculates the gap between current number of PEBs reserved for + * bad eraseblock handling and the required level of PEBs that must be + * reserved, and if necessary, reserves more PEBs to fill that gap, according + * to availability. Should be called with ubi->volumes_lock held. + */ +void ubi_update_reserved(struct ubi_device *ubi) +{ + int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs; + + if (need <= 0 || ubi->avail_pebs == 0) + return; + + need = min_t(int, need, ubi->avail_pebs); + ubi->avail_pebs -= need; + ubi->rsvd_pebs += need; + ubi->beb_rsvd_pebs += need; + ubi_msg(ubi, "reserved more %d PEBs for bad PEB handling", need); +} + +/** + * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad + * eraseblock handling. + * @ubi: UBI device description object + */ +void ubi_calculate_reserved(struct ubi_device *ubi) +{ + /* + * Calculate the actual number of PEBs currently needed to be reserved + * for future bad eraseblock handling. + */ + ubi->beb_rsvd_level = ubi->bad_peb_limit - ubi->bad_peb_count; + if (ubi->beb_rsvd_level < 0) { + ubi->beb_rsvd_level = 0; + ubi_warn(ubi, "number of bad PEBs (%d) is above the expected limit (%d), not reserving any PEBs for bad PEB handling, will use available PEBs (if any)", + ubi->bad_peb_count, ubi->bad_peb_limit); + } +} + +/** + * ubi_check_pattern - check if buffer contains only a certain byte pattern. + * @buf: buffer to check + * @patt: the pattern to check + * @size: buffer size in bytes + * + * This function returns %1 in there are only @patt bytes in @buf, and %0 if + * something else was also found. + */ +int ubi_check_pattern(const void *buf, uint8_t patt, int size) +{ + int i; + + for (i = 0; i < size; i++) + if (((const uint8_t *)buf)[i] != patt) + return 0; + return 1; +} + +/* Normal UBI messages */ +void ubi_msg(const struct ubi_device *ubi, const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + pr_notice(UBI_NAME_STR "%d: %pV\n", ubi->ubi_num, &vaf); + + va_end(args); +} + +/* UBI warning messages */ +void ubi_warn(const struct ubi_device *ubi, const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + pr_warn(UBI_NAME_STR "%d warning: %ps: %pV\n", + ubi->ubi_num, __builtin_return_address(0), &vaf); + + va_end(args); +} + +/* UBI error messages */ +void ubi_err(const struct ubi_device *ubi, const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + pr_err(UBI_NAME_STR "%d error: %ps: %pV\n", + ubi->ubi_num, __builtin_return_address(0), &vaf); + va_end(args); +} -- cgit v1.3.1