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/jffs2/compr_rtime.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 fs/jffs2/compr_rtime.c (limited to 'fs/jffs2/compr_rtime.c') diff --git a/fs/jffs2/compr_rtime.c b/fs/jffs2/compr_rtime.c new file mode 100644 index 000000000..3bd9d2f3b --- /dev/null +++ b/fs/jffs2/compr_rtime.c @@ -0,0 +1,136 @@ +/* + * JFFS2 -- Journalling Flash File System, Version 2. + * + * Copyright © 2001-2007 Red Hat, Inc. + * Copyright © 2004-2010 David Woodhouse + * + * Created by Arjan van de Ven + * + * For licensing information, see the file 'LICENCE' in this directory. + * + * + * + * Very simple lz77-ish encoder. + * + * Theory of operation: Both encoder and decoder have a list of "last + * occurrences" for every possible source-value; after sending the + * first source-byte, the second byte indicated the "run" length of + * matches + * + * The algorithm is intended to only send "whole bytes", no bit-messing. + * + */ + +#include +#include +#include +#include +#include +#include "compr.h" + +/* _compress returns the compressed size, -1 if bigger */ +static int jffs2_rtime_compress(unsigned char *data_in, + unsigned char *cpage_out, + uint32_t *sourcelen, uint32_t *dstlen) +{ + unsigned short positions[256]; + int outpos = 0; + int pos=0; + + if (*dstlen <= 3) + return -1; + + memset(positions,0,sizeof(positions)); + + while (pos < (*sourcelen) && outpos <= (*dstlen)-2) { + int backpos, runlen=0; + unsigned char value; + + value = data_in[pos]; + + cpage_out[outpos++] = data_in[pos++]; + + backpos = positions[value]; + positions[value]=pos; + + while ((backpos < pos) && (pos < (*sourcelen)) && + (data_in[pos]==data_in[backpos++]) && (runlen<255)) { + pos++; + runlen++; + } + cpage_out[outpos++] = runlen; + } + + if (outpos >= pos) { + /* We failed */ + return -1; + } + + /* Tell the caller how much we managed to compress, and how much space it took */ + *sourcelen = pos; + *dstlen = outpos; + return 0; +} + + +static int jffs2_rtime_decompress(unsigned char *data_in, + unsigned char *cpage_out, + uint32_t srclen, uint32_t destlen) +{ + unsigned short positions[256]; + int outpos = 0; + int pos=0; + + memset(positions,0,sizeof(positions)); + + while (outpos destlen) { + return 1; + } + if (backoffs + repeat >= outpos) { + while(repeat) { + cpage_out[outpos++] = cpage_out[backoffs++]; + repeat--; + } + } else { + memcpy(&cpage_out[outpos],&cpage_out[backoffs],repeat); + outpos+=repeat; + } + } + } + return 0; +} + +static struct jffs2_compressor jffs2_rtime_comp = { + .priority = JFFS2_RTIME_PRIORITY, + .name = "rtime", + .compr = JFFS2_COMPR_RTIME, + .compress = &jffs2_rtime_compress, + .decompress = &jffs2_rtime_decompress, +#ifdef JFFS2_RTIME_DISABLED + .disabled = 1, +#else + .disabled = 0, +#endif +}; + +int jffs2_rtime_init(void) +{ + return jffs2_register_compressor(&jffs2_rtime_comp); +} + +void jffs2_rtime_exit(void) +{ + jffs2_unregister_compressor(&jffs2_rtime_comp); +} -- cgit v1.3.1