Hi!
From: Peter Zijlstra peterz@infradead.org
[ Upstream commit be993e44badc448add6a18d6f12b20615692c4c3 ]
The __patch_text() function already applies __opcode_to_mem_*(), so when __opcode_to_mem_*() is not the identity (BE*), it is applied twice, wrecking the instruction.
Fixes: 42e51f187f86 ("arm/ftrace: Use __patch_text()")
I don't see 42e51f187f86 anywhere. Mainline contains
commit 5a735583b764750726621b0396d03e4782911b77 Author: Peter Zijlstra peterz@infradead.org Date: Tue Oct 15 21:07:35 2019 +0200
arm/ftrace: Use __patch_text()
But that one is not present in 4.19, so perhaps we should not need this?
Best regards, Pavel
Reported-by: Dmitry Osipenko digetx@gmail.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Tested-by: Dmitry Osipenko digetx@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org
arch/arm/kernel/ftrace.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index ee673c09aa6c0..dd0215fb6fe23 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -106,13 +106,10 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old, { unsigned long replaced;
- if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
- if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) old = __opcode_to_mem_thumb32(old);
new = __opcode_to_mem_thumb32(new);- } else {
- else old = __opcode_to_mem_arm(old);
new = __opcode_to_mem_arm(new);- }
if (validate) { if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE)) -- 2.20.1