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| author | Steven Rostedt <rostedt@goodmis.org> | 2026-09-02 09:55:01 -0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-09-02 11:08:21 -0400 |
| commit | 4617721c502b2ddaa4e324e86da4997edf738fa5 (patch) | |
| tree | 350aa83b47da0b574a814795392b20b0bed83cbc /arch/powerpc/sysdev/dcr-low.S | |
| download | linux-stable-4617721c502b2ddaa4e324e86da4997edf738fa5.tar.gz linux-stable-4617721c502b2ddaa4e324e86da4997edf738fa5.zip | |
ftrace: Synchronize the initialization of ftrace_opsgrafted
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 <rostedt@goodmis.org>
Diffstat (limited to 'arch/powerpc/sysdev/dcr-low.S')
| -rw-r--r-- | arch/powerpc/sysdev/dcr-low.S | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/dcr-low.S b/arch/powerpc/sysdev/dcr-low.S new file mode 100644 index 000000000..e8401b205 --- /dev/null +++ b/arch/powerpc/sysdev/dcr-low.S @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * "Indirect" DCR access + * + * Copyright (c) 2004 Eugene Surovegin <ebs@ebshome.net> + */ + +#include <linux/export.h> +#include <asm/ppc_asm.h> +#include <asm/processor.h> +#include <asm/bug.h> + +#define DCR_ACCESS_PROLOG(table) \ + cmplwi cr0,r3,1024; \ + rlwinm r3,r3,4,18,27; \ + lis r5,table@h; \ + ori r5,r5,table@l; \ + add r3,r3,r5; \ + bge- 1f; \ + mtctr r3; \ + bctr; \ +1: trap; \ + EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0; \ + blr + +_GLOBAL(__mfdcr) + DCR_ACCESS_PROLOG(__mfdcr_table) +EXPORT_SYMBOL(__mfdcr) + +_GLOBAL(__mtdcr) + DCR_ACCESS_PROLOG(__mtdcr_table) +EXPORT_SYMBOL(__mtdcr) + +__mfdcr_table: + mfdcr r3,0; blr +__mtdcr_table: + mtdcr 0,r4; blr + +dcr = 1 + .rept 1023 + mfdcr r3,dcr; blr + mtdcr dcr,r4; blr + dcr = dcr + 1 + .endr |