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| author | Sean Christopherson <seanjc@google.com> | 2026-04-23 17:54:17 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2026-04-27 22:02:40 +0300 |
| commit | 40c4b47f41b95dff743c841536cb64014e65ef0c (patch) | |
| tree | 8c66a27880f1d37adcb4463c93707fef928d70d9 | |
| parent | 254f49634ee16a731174d2ae34bc50bd5f45e731 (diff) | |
| download | linux-40c4b47f41b95dff743c841536cb64014e65ef0c.tar.xz | |
x86/bug: Add printf() validation to HAVE_ARCH_BUG_FORMAT_ARGS WARNs
Add explicit printf() validation for x86-64's newfangled WARN
implementation, as most (all?) compilers fail to detect basic formatting
issues without the annotation. E.g. even goofs like printing a u64 as a
string aren't detected:
WARN_ONCE(1, "Bad message, %s", vcpu->arch.last_guest_tsc);
32-bit x86 doesn't support HAVE_ARCH_BUG_FORMAT_ARGS and uses generic
implementations that provide printf() validation. This means there's
now a big blind spot is code that is strictly x86-64. Inconveniently,
new features are also frequently x86-64-only.
Fix the blind 64-bit blind spot.
[ dhansen: changelog tweaks to flesh out the 64-bit-only details ]
Fixes: 5b472b6e5bd9 ("x86_64/bug: Implement __WARN_printf()")
Fixes: 11bb4944f014 ("x86/bug: Implement WARN_ONCE()")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/adc1IrD8uqWdaOKv@yzhao56-desk.sh.intel.com
Link: https://patch.msgid.link/20260423145419.459988-2-seanjc@google.com
| -rw-r--r-- | arch/x86/include/asm/bug.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h index 80c1696d8d59..bf3c802654d1 100644 --- a/arch/x86/include/asm/bug.h +++ b/arch/x86/include/asm/bug.h @@ -153,6 +153,7 @@ struct arch_va_list { struct sysv_va_list args; }; extern void *__warn_args(struct arch_va_list *args, struct pt_regs *regs); +static __always_inline __printf(1, 2) void __WARN_validate_printf(const char *fmt, ...) { } #endif /* __ASSEMBLER__ */ #define __WARN_bug_entry(flags, format) ({ \ @@ -172,6 +173,7 @@ extern void *__warn_args(struct arch_va_list *args, struct pt_regs *regs); #define __WARN_print_arg(flags, format, arg...) \ do { \ int __flags = (flags) | BUGFLAG_WARNING | BUGFLAG_ARGS ; \ + __WARN_validate_printf(format, ## arg); \ static_call_mod(WARN_trap)(__WARN_bug_entry(__flags, format), ## arg); \ asm (""); /* inhibit tail-call optimization */ \ } while (0) |