On Wed, Nov 20, 2019 at 11:43 PM Ben Hutchings
[off-list ref] wrote:

On Fri, 2019-11-08 at 22:07 +0100, Arnd Bergmann wrote:
[...]

quoted

--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S

@@ -15,10 +15,8 @@
 /* Offset for the low 32-bit part of a field of long type */
 #if defined(CONFIG_PPC64) && defined(CONFIG_CPU_BIG_ENDIAN)
 #define LOPART       4
-#define TSPEC_TV_SEC TSPC64_TV_SEC+LOPART
 #else
 #define LOPART       0
-#define TSPEC_TV_SEC TSPC32_TV_SEC
 #endif

      .text

@@ -192,7 +190,7 @@ V_FUNCTION_BEGIN(__kernel_time)
      bl      __get_datapage@local
      mr      r9, r3                  /* datapage ptr in r9 */

-     lwz     r3,STAMP_XTIME+TSPEC_TV_SEC(r9)
+     lwz     r3,STAMP_XTIME_SEC+LOWPART(r9)

"LOWPART" should be "LOPART".

Thanks, fixed both instances in a patch on top now. I considered folding
it into the original patch, but as it's close to the merge window I'd
rather not rebase it, and this way I also give you credit for finding the bug.

I'm surprised that the 0-day bot did not report this already.

Thanks fro the careful review!

        Arnd

commit 1c11ca7a0584ddede5b8c93057b40d31e8a96d3d (HEAD)
Author: Arnd Bergmann [off-list ref]
Date:   Thu Nov 21 15:19:49 2019 +0100

    y2038: fix typo in powerpc vdso "LOPART"

    The earlier patch introduced a typo, change LOWPART back to
    LOPART.

    Fixes: 176ed98c8a76 ("y2038: vdso: powerpc: avoid timespec references")
    Reported-by: Ben Hutchings [off-list ref]
    Signed-off-by: Arnd Bergmann [off-list ref]

diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S

b/arch/powerpc/kernel/vdso32/gettimeofday.S
index a7180b0f4aa1..c8e6902cb01b 100644

--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S

@@ -190,7 +190,7 @@ V_FUNCTION_BEGIN(__kernel_time)
        bl      __get_datapage@local
        mr      r9, r3                  /* datapage ptr in r9 */

-       lwz     r3,STAMP_XTIME_SEC+LOWPART(r9)
+       lwz     r3,STAMP_XTIME_SEC+LOPART(r9)

        cmplwi  r11,0                   /* check if t is NULL */
        beq     2f

@@ -266,7 +266,7 @@ __do_get_tspec:
         * as a 32.32 fixed-point number in r3 and r4.
         * Load & add the xtime stamp.
         */
-       lwz     r5,STAMP_XTIME_SEC+LOWPART(r9)
+       lwz     r5,STAMP_XTIME_SEC+LOPART(r9)

        lwz     r6,STAMP_SEC_FRAC(r9)
        addc    r4,r4,r6
        adde    r3,r3,r5