On Tue, 28 Aug 2018 08:55:14 +0200 (CEST) Jiri Kosina <[email protected]> wrote:
> From: Jiri Kosina <[email protected]> > > text_poke() and text_poke_bp() must be called with text_mutex held. > Let's put proper lockdep anotation in place instead of just mentioning > the requirement in comment. Thank you! Acked-by: Masami Hiramatsu <[email protected]> > > Reported-by: Peter Zijlstra <[email protected]> > Signed-off-by: Jiri Kosina <[email protected]> > --- > arch/x86/kernel/alternative.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c > index 014f214da581..b9d5e7c9ef43 100644 > --- a/arch/x86/kernel/alternative.c > +++ b/arch/x86/kernel/alternative.c > @@ -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. > > -- > Jiri Kosina > SUSE Labs > -- Masami Hiramatsu <[email protected]>
