From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: [PATCH 4.9 23/29] objtool: Detect RIP-relative switch table references
Date: Mon, 4 Jun 2018 08:58:19 +0200 [thread overview]
Message-ID: <20180604065803.083869458@linuxfoundation.org> (raw)
In-Reply-To: <20180604065802.157744637@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Josh Poimboeuf <jpoimboe@redhat.com>
commit 6f5ec2993b1f39aed12fa6fd56e8dc2272ee8a33 upstream.
Typically a switch table can be found by detecting a .rodata access
followed an indirect jump:
1969: 4a 8b 0c e5 00 00 00 mov 0x0(,%r12,8),%rcx
1970: 00
196d: R_X86_64_32S .rodata+0x438
1971: e9 00 00 00 00 jmpq 1976 <dispc_runtime_suspend+0xb6a>
1972: R_X86_64_PC32 __x86_indirect_thunk_rcx-0x4
Randy Dunlap reported a case (seen with GCC 4.8) where the .rodata
access uses RIP-relative addressing:
19bd: 48 8b 3d 00 00 00 00 mov 0x0(%rip),%rdi # 19c4 <dispc_runtime_suspend+0xbb8>
19c0: R_X86_64_PC32 .rodata+0x45c
19c4: e9 00 00 00 00 jmpq 19c9 <dispc_runtime_suspend+0xbbd>
19c5: R_X86_64_PC32 __x86_indirect_thunk_rdi-0x4
In this case the relocation addend needs to be adjusted accordingly in
order to find the location of the switch table.
The fix is for case 3 (as described in the comments), but also make the
existing case 1 & 2 checks more precise by only adjusting the addend for
R_X86_64_PC32 relocations.
This fixes the following warnings:
drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_suspend()+0xbb8: sibling call from callable instruction with modified stack frame
drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_resume()+0xcc5: sibling call from callable instruction with modified stack frame
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b6098294fd67afb69af8c47c9883d7a68bf0f8ea.1526305958.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/objtool/check.c | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -898,24 +898,24 @@ static struct rela *find_switch_table(st
{
struct rela *text_rela, *rodata_rela;
struct instruction *orig_insn = insn;
+ unsigned long table_offset;
+ /* case 1 & 2 */
text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len);
if (text_rela && text_rela->sym == file->rodata->sym &&
!find_symbol_containing(file->rodata, text_rela->addend)) {
- /* case 1 */
- rodata_rela = find_rela_by_dest(file->rodata,
- text_rela->addend);
- if (rodata_rela)
- return rodata_rela;
+ table_offset = text_rela->addend;
+ if (text_rela->type == R_X86_64_PC32) {
+ /* case 2 */
+ table_offset += 4;
+ file->ignore_unreachables = true;
+ }
- /* case 2 */
- rodata_rela = find_rela_by_dest(file->rodata,
- text_rela->addend + 4);
+ rodata_rela = find_rela_by_dest(file->rodata, table_offset);
if (!rodata_rela)
return NULL;
- file->ignore_unreachables = true;
return rodata_rela;
}
@@ -949,18 +949,21 @@ static struct rela *find_switch_table(st
if (!text_rela || text_rela->sym != file->rodata->sym)
continue;
+ table_offset = text_rela->addend;
+ if (text_rela->type == R_X86_64_PC32)
+ table_offset += 4;
+
/*
* Make sure the .rodata address isn't associated with a
* symbol. gcc jump tables are anonymous data.
*/
- if (find_symbol_containing(file->rodata, text_rela->addend))
+ if (find_symbol_containing(file->rodata, table_offset))
continue;
- rodata_rela = find_rela_by_dest(file->rodata, text_rela->addend);
- if (!rodata_rela)
- continue;
-
- return rodata_rela;
+ /* mov [rodata addr], %reg */
+ rodata_rela = find_rela_by_dest(file->rodata, table_offset);
+ if (rodata_rela)
+ return rodata_rela;
}
return NULL;
next prev parent reply other threads:[~2018-06-04 7:00 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 6:57 [PATCH 4.9 00/29] 4.9.106-stable review Greg Kroah-Hartman
2018-06-04 6:57 ` [PATCH 4.9 01/29] objtool: Improve detection of BUG() and other dead ends Greg Kroah-Hartman
2018-06-04 6:57 ` [PATCH 4.9 02/29] objtool: Move checking code to check.c Greg Kroah-Hartman
2018-06-04 6:57 ` [PATCH 4.9 03/29] tools lib: Add for_each_clear_bit macro Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 04/29] tools: add more bitmap functions Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 05/29] tools: enable endian checks for all sparse builds Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 06/29] tools include: Introduce linux/compiler-gcc.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 07/29] radix tree test suite: Remove types.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 08/29] tools include: Adopt __compiletime_error Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 09/29] tools include: Introduce atomic_cmpxchg_{relaxed,release}() Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 10/29] tools include: Add UINT_MAX def to kernel.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 11/29] tools include: Adopt kernels refcount.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 12/29] perf tools: Force fixdep compilation at the start of the build Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 13/29] perf tools: Move headers check into bash script Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 14/29] tools include uapi: Grab copies of stat.h and fcntl.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 15/29] tools include: Introduce linux/bug.h, from the kernel sources Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 16/29] tools include: Adopt __same_type() and __must_be_array() from the kernel Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 17/29] tools include: Move ARRAY_SIZE() to linux/kernel.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 18/29] tools include: Drop ARRAY_SIZE() definition from linux/hashtable.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 19/29] tools include: Include missing headers for fls() and types in linux/log2.h Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 20/29] objtool: sync up with the 4.14.47 version of objtool Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 21/29] objtool: Support GCC 8s cold subfunctions Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 22/29] objtool: Support GCC 8 switch tables Greg Kroah-Hartman
2018-06-04 6:58 ` Greg Kroah-Hartman [this message]
2018-06-04 6:58 ` [PATCH 4.9 24/29] objtool: Detect RIP-relative switch table references, part 2 Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 25/29] objtool: Fix "noreturn" detection for recursive sibling calls Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 26/29] objtool, x86: Add several functions and files to the objtool whitelist Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 27/29] perf/tools: header file sync up Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 28/29] objtool: header file sync-up Greg Kroah-Hartman
2018-06-04 6:58 ` [PATCH 4.9 29/29] x86/xen: Add unwind hint annotations to xen_setup_gdt Greg Kroah-Hartman
2018-06-04 10:15 ` [PATCH 4.9 00/29] 4.9.106-stable review Guenter Roeck
2018-06-04 11:27 ` Greg Kroah-Hartman
2018-06-04 12:21 ` Greg Kroah-Hartman
2018-06-04 16:16 ` Guenter Roeck
2018-06-04 16:54 ` Guenter Roeck
2018-06-04 16:57 ` Greg Kroah-Hartman
2018-06-04 17:04 ` Guenter Roeck
2018-06-04 16:58 ` Greg Kroah-Hartman
2018-06-04 19:46 ` Shuah Khan
2018-06-05 6:14 ` Naresh Kamboju
[not found] ` <5b152b7c.1c69fb81.3f04a.096f@mx.google.com>
[not found] ` <7hr2lmjgcd.fsf@baylibre.com>
2018-06-05 10:51 ` Mark Brown
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