Applied. Thanks! Alex
On Wed, Feb 25, 2026 at 1:04 PM Kees Cook <[email protected]> wrote: > > 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 <[email protected]> > --- > v2: use temp u64 to avoid 64-bit division later > v1: https://lore.kernel.org/lkml/[email protected]/ > Cc: Alex Deucher <[email protected]> > Cc: "Christian König" <[email protected]> > Cc: David Airlie <[email protected]> > Cc: Simona Vetter <[email protected]> > Cc: YiPeng Chai <[email protected]> > Cc: Tao Zhou <[email protected]> > Cc: Hawking Zhang <[email protected]> > Cc: <[email protected]> > Cc: <[email protected]> > --- > drivers/gpu/drm/amd/ras/rascore/ras_core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/ras/rascore/ras_core.c > b/drivers/gpu/drm/amd/ras/rascore/ras_core.c > index 01122b55c98a..02bbee64a5bd 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; > -- > 2.34.1 >
