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authorPeter Zijlstra <peterz@infradead.org>2019-03-01 13:15:49 +0300
committerIngo Molnar <mingo@kernel.org>2019-04-03 12:02:24 +0300
commit7697eee3ddd768a1fd78c1e687afaa6c5aa5072d (patch)
tree2aa9fcbbf6b43a95793edcbc02dfbc5dd8bb9e3f /tools/objtool/check.c
parentaaf5c623b915d64beba676b8c2e9708d1fda94d6 (diff)
downloadlinux-7697eee3ddd768a1fd78c1e687afaa6c5aa5072d.tar.xz
objtool: Add --backtrace support
For when you want to know the path that reached your fail state: $ ./objtool check --no-fp --backtrace arch/x86/lib/usercopy_64.o arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0x3: UACCESS disable without MEMOPs: __clear_user() arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x3a: (alt) arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x2e: (branch) arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x18: (branch) arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0xffffffffffffffff: (branch) arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x5: (alt) arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x0: <=== (func) 0000000000000000 <__clear_user>: 0: e8 00 00 00 00 callq 5 <__clear_user+0x5> 1: R_X86_64_PLT32 __fentry__-0x4 5: 90 nop 6: 90 nop 7: 90 nop 8: 48 89 f0 mov %rsi,%rax b: 48 c1 ee 03 shr $0x3,%rsi f: 83 e0 07 and $0x7,%eax 12: 48 89 f1 mov %rsi,%rcx 15: 48 85 c9 test %rcx,%rcx 18: 74 0f je 29 <__clear_user+0x29> 1a: 48 c7 07 00 00 00 00 movq $0x0,(%rdi) 21: 48 83 c7 08 add $0x8,%rdi 25: ff c9 dec %ecx 27: 75 f1 jne 1a <__clear_user+0x1a> 29: 48 89 c1 mov %rax,%rcx 2c: 85 c9 test %ecx,%ecx 2e: 74 0a je 3a <__clear_user+0x3a> 30: c6 07 00 movb $0x0,(%rdi) 33: 48 ff c7 inc %rdi 36: ff c9 dec %ecx 38: 75 f6 jne 30 <__clear_user+0x30> 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 48 89 c8 mov %rcx,%rax 40: c3 retq Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/objtool/check.c')
-rw-r--r--tools/objtool/check.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 8d8191f25381..ccc66af5907f 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1885,8 +1885,11 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
if (!insn->ignore_alts) {
list_for_each_entry(alt, &insn->alts, list) {
ret = validate_branch(file, alt->insn, state);
- if (ret)
- return 1;
+ if (ret) {
+ if (backtrace)
+ BT_FUNC("(alt)", insn);
+ return ret;
+ }
}
}
@@ -1933,8 +1936,11 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
insn->jump_dest->func->pfunc == func)) {
ret = validate_branch(file, insn->jump_dest,
state);
- if (ret)
- return 1;
+ if (ret) {
+ if (backtrace)
+ BT_FUNC("(branch)", insn);
+ return ret;
+ }
} else if (func && has_modified_stack_frame(&state)) {
WARN_FUNC("sibling call from callable instruction with modified stack frame",
@@ -2005,6 +2011,8 @@ static int validate_unwind_hints(struct objtool_file *file)
for_each_insn(file, insn) {
if (insn->hint && !insn->visited) {
ret = validate_branch(file, insn, state);
+ if (ret && backtrace)
+ BT_FUNC("<=== (hint)", insn);
warnings += ret;
}
}
@@ -2133,6 +2141,8 @@ static int validate_functions(struct objtool_file *file)
continue;
ret = validate_branch(file, insn, state);
+ if (ret && backtrace)
+ BT_FUNC("<=== (func)", insn);
warnings += ret;
}
}