| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 19 Apr 2024 14:09:49 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Daniel Sneddon <daniel.sneddon@...ux.intel.com>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Alexandre Chartre <alexandre.chartre@...cle.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Peter Zijlstra <peterz@...radead.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Sean Christopherson <seanjc@...gle.com>,
Andrew Cooper <andrew.cooper3@...rix.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Nikolay Borisov <nik.borisov@...e.com>,
KP Singh <kpsingh@...nel.org>,
Waiman Long <longman@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Ingo Molnar <mingo@...nel.org>,
"Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH v4 3/5] x86/syscall: Mark exit[_group] syscall handlers __noreturn
The direct-call syscall dispatch functions don't know that the exit()
and exit_group() syscall handlers don't return. As a result the call
sites aren't optimized accordingly.
Fix that by marking those exit syscall declarations as __noreturn.
Fixes the following warnings:
vmlinux.o: warning: objtool: x64_sys_call+0x2804: __x64_sys_exit() is missing a __noreturn annotation
vmlinux.o: warning: objtool: ia32_sys_call+0x29b6: __ia32_sys_exit_group() is missing a __noreturn annotation
Fixes: 7390db8aea0d ("x86/bhi: Add support for clearing branch history at syscall entry")
Reported-by: "Paul E. McKenney" <paulmck@...nel.org>
Closes: https://lkml.kernel.org/lkml/6dba9b32-db2c-4e6d-9500-7a08852f17a3@paulmck-laptop
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
arch/x86/entry/syscall_64.c | 4 ++++
arch/x86/entry/syscall_x32.c | 4 ++++
arch/x86/entry/syscalls/syscall_64.tbl | 6 +++---
arch/x86/um/sys_call_table_32.c | 1 +
arch/x86/um/sys_call_table_64.c | 1 +
scripts/syscalltbl.sh | 6 ++++--
tools/objtool/noreturns.h | 4 ++++
7 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
index 96ea1f8a1d3f..ff36a993a07e 100644
--- a/arch/x86/entry/syscall_64.c
+++ b/arch/x86/entry/syscall_64.c
@@ -8,9 +8,13 @@
#include <asm/syscall.h>
#define __SYSCALL(nr, sym) extern long __x64_##sym(const struct pt_regs *);
+#define __SYSCALL_NORETURN(nr, sym) extern long __noreturn __x64_##sym(const struct pt_regs *);
#include <asm/syscalls_64.h>
#undef __SYSCALL
+#undef __SYSCALL_NORETURN
+#define __SYSCALL_NORETURN __SYSCALL
+
#define __SYSCALL(nr, sym) __x64_##sym,
const sys_call_ptr_t sys_call_table[] = {
#include <asm/syscalls_64.h>
diff --git a/arch/x86/entry/syscall_x32.c b/arch/x86/entry/syscall_x32.c
index 5aef4230faca..4221ecce6e68 100644
--- a/arch/x86/entry/syscall_x32.c
+++ b/arch/x86/entry/syscall_x32.c
@@ -8,9 +8,13 @@
#include <asm/syscall.h>
#define __SYSCALL(nr, sym) extern long __x64_##sym(const struct pt_regs *);
+#define __SYSCALL_NORETURN(nr, sym) extern long __noreturn __x64_##sym(const struct pt_regs *);
#include <asm/syscalls_x32.h>
#undef __SYSCALL
+#undef __SYSCALL_NORETURN
+#define __SYSCALL_NORETURN __SYSCALL
+
#define __SYSCALL(nr, sym) __x64_##sym,
const sys_call_ptr_t x32_sys_call_table[] = {
#include <asm/syscalls_x32.h>
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 7e8d46f4147f..6695105d21b5 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -2,7 +2,7 @@
# 64-bit system call numbers and entry vectors
#
# The format is:
-# <number> <abi> <name> <entry point>
+# <number> <abi> <name> <entry point> [0 noreturn]
#
# The __x64_sys_*() stubs are created on-the-fly for sys_*() system calls
#
@@ -68,7 +68,7 @@
57 common fork sys_fork
58 common vfork sys_vfork
59 64 execve sys_execve
-60 common exit sys_exit
+60 common exit sys_exit 0 noreturn
61 common wait4 sys_wait4
62 common kill sys_kill
63 common uname sys_newuname
@@ -239,7 +239,7 @@
228 common clock_gettime sys_clock_gettime
229 common clock_getres sys_clock_getres
230 common clock_nanosleep sys_clock_nanosleep
-231 common exit_group sys_exit_group
+231 common exit_group sys_exit_group 0 noreturn
232 common epoll_wait sys_epoll_wait
233 common epoll_ctl sys_epoll_ctl
234 common tgkill sys_tgkill
diff --git a/arch/x86/um/sys_call_table_32.c b/arch/x86/um/sys_call_table_32.c
index 89df5d89d664..c7d4bf955d2b 100644
--- a/arch/x86/um/sys_call_table_32.c
+++ b/arch/x86/um/sys_call_table_32.c
@@ -24,6 +24,7 @@
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
#define __SYSCALL(nr, sym) extern asmlinkage long sym(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
+#define __SYSCALL_NORETURN __SYSCALL
#include <asm/syscalls_32.h>
#undef __SYSCALL
diff --git a/arch/x86/um/sys_call_table_64.c b/arch/x86/um/sys_call_table_64.c
index b0b4cfd2308c..4760c40ae5cd 100644
--- a/arch/x86/um/sys_call_table_64.c
+++ b/arch/x86/um/sys_call_table_64.c
@@ -19,6 +19,7 @@
#define sys_ioperm sys_ni_syscall
#define __SYSCALL(nr, sym) extern asmlinkage long sym(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
+#define __SYSCALL_NORETURN __SYSCALL
#include <asm/syscalls_64.h>
#undef __SYSCALL
diff --git a/scripts/syscalltbl.sh b/scripts/syscalltbl.sh
index 6abe143889ef..16487d47e06a 100755
--- a/scripts/syscalltbl.sh
+++ b/scripts/syscalltbl.sh
@@ -54,7 +54,7 @@ nxt=0
grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
- while read nr abi name native compat ; do
+ while read nr abi name native compat noreturn; do
if [ $nxt -gt $nr ]; then
echo "error: $infile: syscall table is not sorted or duplicates the same syscall number" >&2
@@ -66,7 +66,9 @@ grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
nxt=$((nxt + 1))
done
- if [ -n "$compat" ]; then
+ if [ -n "$noreturn" ]; then
+ echo "__SYSCALL_NORETURN($nr, $native)"
+ elif [ -n "$compat" ]; then
echo "__SYSCALL_WITH_COMPAT($nr, $native, $compat)"
elif [ -n "$native" ]; then
echo "__SYSCALL($nr, $native)"
diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h
index 7ebf29c91184..1e8141ef1b15 100644
--- a/tools/objtool/noreturns.h
+++ b/tools/objtool/noreturns.h
@@ -7,12 +7,16 @@
* Yes, this is unfortunate. A better solution is in the works.
*/
NORETURN(__fortify_panic)
+NORETURN(__ia32_sys_exit)
+NORETURN(__ia32_sys_exit_group)
NORETURN(__kunit_abort)
NORETURN(__module_put_and_kthread_exit)
NORETURN(__reiserfs_panic)
NORETURN(__stack_chk_fail)
NORETURN(__tdx_hypercall_failed)
NORETURN(__ubsan_handle_builtin_unreachable)
+NORETURN(__x64_sys_exit)
+NORETURN(__x64_sys_exit_group)
NORETURN(arch_cpu_idle_dead)
NORETURN(bch2_trans_in_restart_error)
NORETURN(bch2_trans_restart_error)
--
2.44.0
Powered by blists - more mailing lists