diff mbox series

[v6,39/44] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS

Message ID 20220905122452.2258262-40-glider@google.com (mailing list archive)
State New
Headers show
Series Add KernelMemorySanitizer infrastructure | expand

Commit Message

Alexander Potapenko Sept. 5, 2022, 12:24 p.m. UTC 
dentry_string_cmp() calls read_word_at_a_time(), which might read
uninitialized bytes to optimize string comparisons.
Disabling CONFIG_DCACHE_WORD_ACCESS should prohibit this optimization,
as well as (probably) similar ones.

Suggested-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
---
Link: https://linux-review.googlesource.com/id/I4c0073224ac2897cafb8c037362c49dda9cfa133
---
 arch/x86/Kconfig | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 33f4d4baba079..697da8dae1418 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -128,7 +128,9 @@  config X86
 	select CLKEVT_I8253
 	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
 	select CLOCKSOURCE_WATCHDOG
-	select DCACHE_WORD_ACCESS
+	# Word-size accesses may read uninitialized data past the trailing \0
+	# in strings and cause false KMSAN reports.
+	select DCACHE_WORD_ACCESS		if !KMSAN
 	select DYNAMIC_SIGFRAME
 	select EDAC_ATOMIC_SCRUB
 	select EDAC_SUPPORT