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/arm/lib/io-readsl.S | 76 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 arch/arm/lib/io-readsl.S (limited to 'arch/arm/lib/io-readsl.S') diff --git a/arch/arm/lib/io-readsl.S b/arch/arm/lib/io-readsl.S new file mode 100644 index 000000000..d9f6b372b --- /dev/null +++ b/arch/arm/lib/io-readsl.S @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/arch/arm/lib/io-readsl.S + * + * Copyright (C) 1995-2000 Russell King + */ +#include +#include + +ENTRY(__raw_readsl) + teq r2, #0 @ do we have to check for the zero len? + reteq lr + ands ip, r1, #3 + bne 3f + + subs r2, r2, #4 + bmi 2f + stmfd sp!, {r4, lr} +1: ldr r3, [r0, #0] + ldr r4, [r0, #0] + ldr ip, [r0, #0] + ldr lr, [r0, #0] + subs r2, r2, #4 + stmia r1!, {r3, r4, ip, lr} + bpl 1b + ldmfd sp!, {r4, lr} +2: movs r2, r2, lsl #31 + ldrcs r3, [r0, #0] + ldrcs ip, [r0, #0] + stmiacs r1!, {r3, ip} + ldrne r3, [r0, #0] + strne r3, [r1, #0] + ret lr + +3: ldr r3, [r0] + cmp ip, #2 + mov ip, r3, get_byte_0 + strb ip, [r1], #1 + bgt 6f + mov ip, r3, get_byte_1 + strb ip, [r1], #1 + beq 5f + mov ip, r3, get_byte_2 + strb ip, [r1], #1 + +4: subs r2, r2, #1 + mov ip, r3, lspull #24 + ldrne r3, [r0] + orrne ip, ip, r3, lspush #8 + strne ip, [r1], #4 + bne 4b + b 8f + +5: subs r2, r2, #1 + mov ip, r3, lspull #16 + ldrne r3, [r0] + orrne ip, ip, r3, lspush #16 + strne ip, [r1], #4 + bne 5b + b 7f + +6: subs r2, r2, #1 + mov ip, r3, lspull #8 + ldrne r3, [r0] + orrne ip, ip, r3, lspush #24 + strne ip, [r1], #4 + bne 6b + + mov r3, ip, get_byte_2 + strb r3, [r1, #2] +7: mov r3, ip, get_byte_1 + strb r3, [r1, #1] +8: mov r3, ip, get_byte_0 + strb r3, [r1, #0] + ret lr +ENDPROC(__raw_readsl) -- cgit v1.3.1