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 --- arch/mips/lib/mips-atomic.c | 113 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) create mode 100644 arch/mips/lib/mips-atomic.c (limited to 'arch/mips/lib/mips-atomic.c') diff --git a/arch/mips/lib/mips-atomic.c b/arch/mips/lib/mips-atomic.c new file mode 100644 index 000000000..a9b72eacf --- /dev/null +++ b/arch/mips/lib/mips-atomic.c @@ -0,0 +1,113 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003 by Ralf Baechle + * Copyright (C) 1996 by Paul M. Antoine + * Copyright (C) 1999 Silicon Graphics + * Copyright (C) 2000 MIPS Technologies, Inc. + */ +#include +#include +#include +#include +#include +#include + +#if !defined(CONFIG_CPU_HAS_DIEI) + +/* + * For cli() we have to insert nops to make sure that the new value + * has actually arrived in the status register before the end of this + * macro. + * R4000/R4400 need three nops, the R4600 two nops and the R10000 needs + * no nops at all. + */ +/* + * For TX49, operating only IE bit is not enough. + * + * If mfc0 $12 follows store and the mfc0 is last instruction of a + * page and fetching the next instruction causes TLB miss, the result + * of the mfc0 might wrongly contain EXL bit. + * + * ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008 + * + * Workaround: mask EXL bit of the result or place a nop before mfc0. + */ +notrace void arch_local_irq_disable(void) +{ + preempt_disable_notrace(); + + __asm__ __volatile__( + " .set push \n" + " .set noat \n" + " mfc0 $1,$12 \n" + " ori $1,0x1f \n" + " xori $1,0x1f \n" + " .set noreorder \n" + " mtc0 $1,$12 \n" + " " __stringify(__irq_disable_hazard) " \n" + " .set pop \n" + : /* no outputs */ + : /* no inputs */ + : "memory"); + + preempt_enable_notrace(); +} +EXPORT_SYMBOL(arch_local_irq_disable); + +notrace unsigned long arch_local_irq_save(void) +{ + unsigned long flags; + + preempt_disable_notrace(); + + __asm__ __volatile__( + " .set push \n" + " .set reorder \n" + " .set noat \n" + " mfc0 %[flags], $12 \n" + " ori $1, %[flags], 0x1f \n" + " xori $1, 0x1f \n" + " .set noreorder \n" + " mtc0 $1, $12 \n" + " " __stringify(__irq_disable_hazard) " \n" + " .set pop \n" + : [flags] "=r" (flags) + : /* no inputs */ + : "memory"); + + preempt_enable_notrace(); + + return flags; +} +EXPORT_SYMBOL(arch_local_irq_save); + +notrace void arch_local_irq_restore(unsigned long flags) +{ + unsigned long __tmp1; + + preempt_disable_notrace(); + + __asm__ __volatile__( + " .set push \n" + " .set noreorder \n" + " .set noat \n" + " mfc0 $1, $12 \n" + " andi %[flags], 1 \n" + " ori $1, 0x1f \n" + " xori $1, 0x1f \n" + " or %[flags], $1 \n" + " mtc0 %[flags], $12 \n" + " " __stringify(__irq_disable_hazard) " \n" + " .set pop \n" + : [flags] "=r" (__tmp1) + : "0" (flags) + : "memory"); + + preempt_enable_notrace(); +} +EXPORT_SYMBOL(arch_local_irq_restore); + +#endif /* !CONFIG_CPU_HAS_DIEI */ -- cgit v1.3.1