2023-02-16 20:36:08

by Josh Poimboeuf

Subject: [PATCH] objtool: Fix ORC 'signal' propagation

There have been some recently reported ORC unwinder warnings like:

WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271

And a KASAN warning:

BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)

It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.

Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/oe-lkp/[email protected]
Reported-by: Dmitry Vyukov <[email protected]>
Link: https://lkml.kernel.org/lkml/CACT4Y+YzZb2vscjBLiJ-p-ghbu77o851gbESfE=nZebXqfgE4g@mail.gmail.com/
Signed-off-by: Josh Poimboeuf <[email protected]>
---
tools/objtool/check.c | 1 +
tools/objtool/include/objtool/cfi.h | 1 +
tools/objtool/orc_gen.c | 1 +
3 files changed, 3 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 7c40bd51c75a..8b242634bc51 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2266,6 +2266,7 @@ static int read_unwind_hints(struct objtool_file *file)

cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
cfi.type = hint->type;
+ cfi.signal = hint->signal;
cfi.end = hint->end;

insn->cfi = cfi_hash_find_or_add(&cfi);
diff --git a/tools/objtool/include/objtool/cfi.h b/tools/objtool/include/objtool/cfi.h
index f11d1ac1dadf..b1258e79a1b7 100644
--- a/tools/objtool/include/objtool/cfi.h
+++ b/tools/objtool/include/objtool/cfi.h
@@ -34,6 +34,7 @@ struct cfi_state {
unsigned char type;
bool bp_scratch;
bool drap;
+ bool signal;
bool end;
};

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 1f22b7ebae58..57a4527d5988 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -27,6 +27,7 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
}

orc->end = cfi->end;
+ orc->signal = cfi->signal;

if (cfi->cfa.base == CFI_UNDEFINED) {
orc->sp_reg = ORC_REG_UNDEFINED;
--
2.39.1

2023-02-21 15:45:06

by tip-bot2 for Alexey Makhalov

Subject: [tip: objtool/core] objtool: Fix ORC 'signal' propagation

The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 801d48faf6bbf985d14aa1027889f3a3fe4206f1
Gitweb: https://git.kernel.org/tip/801d48faf6bbf985d14aa1027889f3a3fe4206f1
Author: Josh Poimboeuf <[email protected]>
AuthorDate: Thu, 16 Feb 2023 12:34:41 -08:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Tue, 21 Feb 2023 16:40:14 +01:00

objtool: Fix ORC 'signal' propagation

There have been some recently reported ORC unwinder warnings like:

WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271

And a KASAN warning:

BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)

It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.

Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/97eef9db60cd86d376a9a40d49d77bb67a8f6526.1676579666.git.jpoimboe@kernel.org
---
tools/objtool/check.c | 1 +
tools/objtool/include/objtool/cfi.h | 1 +
tools/objtool/orc_gen.c | 1 +
3 files changed, 3 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index b0b467d..5822de3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2330,6 +2330,7 @@ static int read_unwind_hints(struct objtool_file *file)

cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
cfi.type = hint->type;
+ cfi.signal = hint->signal;
cfi.end = hint->end;

insn->cfi = cfi_hash_find_or_add(&cfi);
diff --git a/tools/objtool/include/objtool/cfi.h b/tools/objtool/include/objtool/cfi.h
index f11d1ac..b1258e7 100644
--- a/tools/objtool/include/objtool/cfi.h
+++ b/tools/objtool/include/objtool/cfi.h
@@ -34,6 +34,7 @@ struct cfi_state {
unsigned char type;
bool bp_scratch;
bool drap;
+ bool signal;
bool end;
};

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 1f22b7e..57a4527 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -27,6 +27,7 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
}

orc->end = cfi->end;
+ orc->signal = cfi->signal;

if (cfi->cfa.base == CFI_UNDEFINED) {
orc->sp_reg = ORC_REG_UNDEFINED;

2023-02-23 08:32:14

by tip-bot2 for Alexey Makhalov

Subject: [tip: objtool/core] objtool: Fix ORC 'signal' propagation

The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 00c8f01c4e84637c3db76f368b8687cb61f4dd9d
Gitweb: https://git.kernel.org/tip/00c8f01c4e84637c3db76f368b8687cb61f4dd9d
Author: Josh Poimboeuf <[email protected]>
AuthorDate: Thu, 16 Feb 2023 12:34:41 -08:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Thu, 23 Feb 2023 09:21:50 +01:00

objtool: Fix ORC 'signal' propagation

There have been some recently reported ORC unwinder warnings like:

WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271

And a KASAN warning:

BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)

It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.

Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/97eef9db60cd86d376a9a40d49d77bb67a8f6526.1676579666.git.jpoimboe@kernel.org
---
tools/objtool/check.c | 1 +
tools/objtool/include/objtool/cfi.h | 1 +
tools/objtool/orc_gen.c | 1 +
3 files changed, 3 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index b0b467d..5822de3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2330,6 +2330,7 @@ static int read_unwind_hints(struct objtool_file *file)

cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
cfi.type = hint->type;
+ cfi.signal = hint->signal;
cfi.end = hint->end;

insn->cfi = cfi_hash_find_or_add(&cfi);
diff --git a/tools/objtool/include/objtool/cfi.h b/tools/objtool/include/objtool/cfi.h
index f11d1ac..b1258e7 100644
--- a/tools/objtool/include/objtool/cfi.h
+++ b/tools/objtool/include/objtool/cfi.h
@@ -34,6 +34,7 @@ struct cfi_state {
unsigned char type;
bool bp_scratch;
bool drap;
+ bool signal;
bool end;
};

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 1f22b7e..57a4527 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -27,6 +27,7 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
}

orc->end = cfi->end;
+ orc->signal = cfi->signal;

if (cfi->cfa.base == CFI_UNDEFINED) {
orc->sp_reg = ORC_REG_UNDEFINED;