Commit-ID: c2d75e03d6307bda0e14b616818a6f7b09fd623a Gitweb: http://git.kernel.org/tip/c2d75e03d6307bda0e14b616818a6f7b09fd623a Author: Josh Poimboeuf <[email protected]> AuthorDate: Thu, 17 Nov 2016 09:57:23 -0600 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 18 Nov 2016 09:38:00 +0100
x86/unwind: Prevent KASAN false positive warnings in guess unwinder The guess unwinder scans the entire stack, which can cause KASAN "stack-out-of-bounds" false positive warnings. Tell KASAN to ignore it. Reported-by: Peter Zijlstra <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vince Weaver <[email protected]> Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/61939c0b2b2d63ce97ba59cba3b00fd47c2962cf.1479398226.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/kernel/unwind_guess.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c index 2d721e5..b80e8bf 100644 --- a/arch/x86/kernel/unwind_guess.c +++ b/arch/x86/kernel/unwind_guess.c @@ -7,11 +7,13 @@ unsigned long unwind_get_return_address(struct unwind_state *state) { + unsigned long addr = READ_ONCE_NOCHECK(*state->sp); + if (unwind_done(state)) return 0; return ftrace_graph_ret_addr(state->task, &state->graph_idx, - *state->sp, state->sp); + addr, state->sp); } EXPORT_SYMBOL_GPL(unwind_get_return_address); @@ -23,8 +25,10 @@ bool unwind_next_frame(struct unwind_state *state) return false; do { + unsigned long addr = READ_ONCE_NOCHECK(*state->sp); + for (state->sp++; state->sp < info->end; state->sp++) - if (__kernel_text_address(*state->sp)) + if (__kernel_text_address(addr)) return true; state->sp = info->next_sp;
