[tip: x86/urgent] objtool: Fix stack offset tracking for indirect CFAs

[tip-bot2 for Josh Poimboeuf]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     d8dd25a461e4eec7190cb9d66616aceacc5110ad
Gitweb:        https://git.kernel.org/tip/d8dd25a461e4eec7190cb9d66616aceacc5110ad
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Sat, 25 Apr 2020 05:03:00 -05:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Sat, 25 Apr 2020 12:22:27 +02:00

objtool: Fix stack offset tracking for indirect CFAs

When the current frame address (CFA) is stored on the stack (i.e.,
cfa->base == CFI_SP_INDIRECT), objtool neglects to adjust the stack
offset when there are subsequent pushes or pops.  This results in bad
ORC data at the end of the ENTER_IRQ_STACK macro, when it puts the
previous stack pointer on the stack and does a subsequent push.

This fixes the following unwinder warning:

  WARNING: can't dereference registers at 00000000f0a6bdba for ip interrupt_entry+0x9f/0xa0

Fixes: 627fce14809b ("objtool: Add ORC unwind table generation")
Reported-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Reported-by: Dave Jones <dsj@xxxxxx>
Reported-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Reported-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Reported-by: Joe Mario <jmario@xxxxxxxxxx>
Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/853d5d691b29e250333332f09b8e27410b2d9924.1587808742.git.jpoimboe@xxxxxxxxxx
---
 tools/objtool/check.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4b170fd..e718464 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1449,7 +1449,7 @@ static int update_insn_state_regs(struct instruction *insn, struct insn_state *s
 	struct cfi_reg *cfa = &state->cfa;
 	struct stack_op *op = &insn->stack_op;
 
-	if (cfa->base != CFI_SP)
+	if (cfa->base != CFI_SP && cfa->base != CFI_SP_INDIRECT)
 		return 0;
 
 	/* push */