From: Kees Cook Date: Wed, 25 Feb 2026 17:47:03 +0000 (-0800) Subject: drm/amd/ras: Fix type size of remainder argument X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9f3d543a9f7371622aff389e69010ac6bac69ef8;p=thirdparty%2Flinux.git drm/amd/ras: Fix type size of remainder argument Forcing an int to be dereferenced at uint64_t for div64_u64_rem() runs the risk of endian confusion and stack overflowing writes. Seen while preparing to enable -Warray-bounds globally: In file included from ../arch/x86/include/asm/processor.h:35, from ../include/linux/sched.h:13, from ../include/linux/ratelimit.h:6, from ../include/linux/dev_printk.h:16, from ../drivers/gpu/drm/amd/amdgpu/../ras/ras_mgr/ras_sys.h:29, from ../drivers/gpu/drm/amd/amdgpu/../ras/rascore/ras.h:27, from ../drivers/gpu/drm/amd/amdgpu/../ras/rascore/ras_core.c:24: In function 'div64_u64_rem', inlined from 'ras_core_convert_timestamp_to_time' at ../drivers/gpu/drm/amd/amdgpu/../ras/rascore/ras_core.c:72:9: ../include/linux/math64.h:56:20: error: array subscript 'u64 {aka long long unsigned int}[0]' is partly outside array bounds of 'int[1]' [-Werror=array-bounds=] 56 | *remainder = dividend % divisor; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~ ../drivers/gpu/drm/amd/amdgpu/../ras/rascore/ras_core.c: In function 'ras_core_convert_timestamp_to_time': ../drivers/gpu/drm/amd/amdgpu/../ras/rascore/ras_core.c:70:19: note: object 'remaining_seconds' of size 4 70 | int days, remaining_seconds; | ^~~~~~~~~~~~~~~~~ Use a 64-bit type for the remainder calculation, but leave remaining_seconds as 32-bit to avoid 64-bit division later. The value of remainder will always be less than seconds_per_day, so there's no truncation risk. Fixes: ace232eff50e ("drm/amdgpu: Add ras module files into amdgpu") Signed-off-by: Kees Cook Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/ras/rascore/ras_core.c b/drivers/gpu/drm/amd/ras/rascore/ras_core.c index 3f56f26abd6da..9df05b3963edb 100644 --- a/drivers/gpu/drm/amd/ras/rascore/ras_core.c +++ b/drivers/gpu/drm/amd/ras/rascore/ras_core.c @@ -62,14 +62,16 @@ int ras_core_convert_timestamp_to_time(struct ras_core_context *ras_core, uint64_t timestamp, struct ras_time *tm) { int days_in_month[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; - uint64_t month = 0, day = 0, hour = 0, minute = 0, second = 0; + uint64_t month = 0, day = 0, hour = 0, minute = 0, second = 0, remainder; uint32_t year = 0; int seconds_per_day = 24 * 60 * 60; int seconds_per_hour = 60 * 60; int seconds_per_minute = 60; int days, remaining_seconds; - days = div64_u64_rem(timestamp, seconds_per_day, (uint64_t *)&remaining_seconds); + days = div64_u64_rem(timestamp, seconds_per_day, &remainder); + /* remainder will always be less than seconds_per_day. */ + remaining_seconds = remainder; /* utc_timestamp follows the Unix epoch */ year = 1970;