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 --- fs/squashfs/zstd_wrapper.c | 154 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 154 insertions(+) create mode 100644 fs/squashfs/zstd_wrapper.c (limited to 'fs/squashfs/zstd_wrapper.c') diff --git a/fs/squashfs/zstd_wrapper.c b/fs/squashfs/zstd_wrapper.c new file mode 100644 index 000000000..487fbc51d --- /dev/null +++ b/fs/squashfs/zstd_wrapper.c @@ -0,0 +1,154 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2016-present, Facebook, Inc. + * All rights reserved. + * + * zstd_wrapper.c + */ + +#include +#include +#include +#include +#include + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs.h" +#include "decompressor.h" +#include "page_actor.h" + +struct workspace { + void *mem; + size_t mem_size; + size_t window_size; +}; + +static void *zstd_init(struct squashfs_sb_info *msblk, void *buff) +{ + struct workspace *wksp = kmalloc_obj(*wksp); + + if (wksp == NULL) + goto failed; + wksp->window_size = max_t(size_t, + msblk->block_size, SQUASHFS_METADATA_SIZE); + wksp->mem_size = zstd_dstream_workspace_bound(wksp->window_size); + wksp->mem = vmalloc(wksp->mem_size); + if (wksp->mem == NULL) + goto failed; + + return wksp; + +failed: + ERROR("Failed to allocate zstd workspace\n"); + kfree(wksp); + return ERR_PTR(-ENOMEM); +} + + +static void zstd_free(void *strm) +{ + struct workspace *wksp = strm; + + if (wksp) + vfree(wksp->mem); + kfree(wksp); +} + + +static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm, + struct bio *bio, int offset, int length, + struct squashfs_page_actor *output) +{ + struct workspace *wksp = strm; + zstd_dstream *stream; + size_t total_out = 0; + int error = 0; + zstd_in_buffer in_buf = { NULL, 0, 0 }; + zstd_out_buffer out_buf = { NULL, 0, 0 }; + struct bvec_iter_all iter_all = {}; + struct bio_vec *bvec = bvec_init_iter_all(&iter_all); + + stream = zstd_init_dstream(wksp->window_size, wksp->mem, wksp->mem_size); + + if (!stream) { + ERROR("Failed to initialize zstd decompressor\n"); + return -EIO; + } + + out_buf.size = PAGE_SIZE; + out_buf.dst = squashfs_first_page(output); + if (IS_ERR(out_buf.dst)) { + error = PTR_ERR(out_buf.dst); + goto finish; + } + + for (;;) { + size_t zstd_err; + + if (in_buf.pos == in_buf.size) { + const void *data; + int avail; + + if (!bio_next_segment(bio, &iter_all)) { + error = -EIO; + break; + } + + avail = min(length, ((int)bvec->bv_len) - offset); + data = bvec_virt(bvec); + length -= avail; + in_buf.src = data + offset; + in_buf.size = avail; + in_buf.pos = 0; + offset = 0; + } + + if (out_buf.pos == out_buf.size) { + out_buf.dst = squashfs_next_page(output); + if (IS_ERR(out_buf.dst)) { + error = PTR_ERR(out_buf.dst); + break; + } else if (out_buf.dst == NULL) { + /* Shouldn't run out of pages + * before stream is done. + */ + error = -EIO; + break; + } + out_buf.pos = 0; + out_buf.size = PAGE_SIZE; + } + + total_out -= out_buf.pos; + zstd_err = zstd_decompress_stream(stream, &out_buf, &in_buf); + total_out += out_buf.pos; /* add the additional data produced */ + if (zstd_err == 0) + break; + + if (zstd_is_error(zstd_err)) { + ERROR("zstd decompression error: %d\n", + (int)zstd_get_error_code(zstd_err)); + error = -EIO; + break; + } + } + +finish: + + squashfs_finish_page(output); + + return error ? error : total_out; +} + +const struct squashfs_decompressor squashfs_zstd_comp_ops = { + .init = zstd_init, + .free = zstd_free, + .decompress = zstd_uncompress, + .id = ZSTD_COMPRESSION, + .name = "zstd", + .alloc_buffer = 1, + .supported = 1 +}; -- cgit v1.3.1