diff options
| author | Thomas Gleixner <tglx@kernel.org> | 2026-09-05 10:43:57 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@kernel.org> | 2026-09-07 11:17:54 +0200 |
| commit | 954f7a48fa2ae7310c67729fb556caf726783436 (patch) | |
| tree | f82a37685ce3608923d4bade265c651e7cf391b3 /include | |
| parent | df2908090cda368b01ff43709f51890076c56157 (diff) | |
entry: Guard syscall_enter_audit() invocation with CONFIG_AUDITSYSCALL
A bunch of older cross compilers notably RISCV64 and S390 fail to eliminate
the dead code when CONFIG_AUDITSYSCALL=n. The code in question is:
if (unlikely(audit_context())
syscall_enter_audit(regs);
and in case of CONFIG_AUDITSYSCALL=n:
static inline struct audit_context *audit_context(void)
{
return NULL;
}
which should make the compiler eliminate the syscall_enter_audit()
call. But a RISV64 GCC12 cross compiler translates that into:
if (unlikely(audit_context()))
1c34: 00000097 auipc ra,0x0
1c38: 000080e7 jalr ra # 1c34 <.L785>
1c3c: c511 beqz a0,1c48 <.L787>
syscall_enter_audit(regs);
1c3e: 8526 mv a0,s1
1c40: 00000097 auipc ra,0x0
1c44: 000080e7 jalr ra # 1c40 <.L785+0xc>
and then claims in the failing link:
include/asm-generic/preempt.h:54:(.noinstr.text+0x1a20):
undefined reference to 'syscall_enter_audit'
which is obviously hallucination.
Add an explicit IS_ENABLED(CONFIG_AUDITSYSCALL) check into the condition to
cure this compiler madness.
Fixes: 6f25517010dd ("entry: Rework syscall_audit_enter()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/87tso45bqq.ffs@fw13
Closes: https://lore.kernel.org/oe-kbuild-all/202609031938.ZvZZaRQy-lkp@intel.com/
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/entry-common.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 6574b7183c01..fa2854fed1f2 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -102,7 +102,14 @@ static __always_inline long syscall_trace_enter(struct pt_regs *regs, unsigned l if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) trace_syscall_enter(regs); - if (unlikely(audit_context())) + /* + * The config check works around broken compilers which fail to + * eliminate the dead code in case of CONFIG_AUDITSYSCALL=n as they + * insist on creating a always false runtime condition based on + * audit_context() which returns NULL in that case. The explicit + * IS_ENABLED() check makes that madness go away. + */ + if (IS_ENABLED(CONFIG_AUDITSYSCALL) && unlikely(audit_context())) syscall_enter_audit(regs); return true; |