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x86/alternatives: Lockdep-enforce text_mutex in text_poke*() 

text_poke() and text_poke_bp() must be called with text_mutex held.

Put proper lockdep anotation in place instead of just mentioning the
requirement in a comment.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/nycvar.YFH.7.76.1808280853520.25787@cbobk.fhfr.pm
hifive-unleashed-5.1
Jiri Kosina 2018-08-28 08:55:14 +02:00 committed by Thomas Gleixner
parent f12d11c5c1
commit 9222f60650
1 changed files with 5 additions and 4 deletions
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9
arch/x86/kernel/alternative.c
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@ -684,8 +684,6 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode,
* It means the size must be writable atomically and the address must be aligned
* in a way that permits an atomic write. It also makes sure we fit on a single
* page.
*
* Note: Must be called under text_mutex.
*/
void *text_poke(void *addr, const void *opcode, size_t len)
{
@ -700,6 +698,8 @@ void *text_poke(void *addr, const void *opcode, size_t len)
*/
BUG_ON(!after_bootmem);
lockdep_assert_held(&text_mutex);
if (!core_kernel_text((unsigned long)addr)) {
pages[0] = vmalloc_to_page(addr);
pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
@ -782,8 +782,6 @@ int poke_int3_handler(struct pt_regs *regs)
* - replace the first byte (int3) by the first byte of
* replacing opcode
* - sync cores
*
* Note: must be called under text_mutex.
*/
void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
{
@ -792,6 +790,9 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
bp_int3_handler = handler;
bp_int3_addr = (u8 *)addr + sizeof(int3);
bp_patching_in_progress = true;
lockdep_assert_held(&text_mutex);
/*
* Corresponding read barrier in int3 notifier for making sure the
* in_progress and handler are correctly ordered wrt. patching.