[PATCH] powerpc/mm/hash64: Fix might_have_hea() check

* [PATCH] powerpc/mm/hash64: Fix might_have_hea() check
@ 2016-10-11 10:15 Michael Ellerman
  2016-10-19  2:17 ` Michael Ellerman
  0 siblings, 1 reply; 2+ messages in thread
From: Michael Ellerman @ 2016-10-11 10:15 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: jstancek, kda, benh

In commit 2b4e3ad8f579 ("powerpc/mm/hash64: Don't test for machine type
to detect HEA special case") we changed the logic in might_have_hea()
to check FW_FEATURE_SPLPAR rather than machine_is(pseries).

However the check was incorrectly negated, leading to crashes on
machines with HEA adapters, such as:

  mm: Hashing failure ! EA=0xd000080080004040 access=0x800000000000000e current=NetworkManager
      trap=0x300 vsid=0x13d349c ssize=1 base psize=2 psize 2 pte=0xc0003cc033e701ae
  Unable to handle kernel paging request for data at address 0xd000080080004040
  Call Trace:
    .ehea_create_cq+0x148/0x340 [ehea] (unreliable)
    .ehea_up+0x258/0x1200 [ehea]
    .ehea_open+0x44/0x1a0 [ehea]
    ...

Fix it by removing the negation.

Fixes: 2b4e3ad8f579 ("powerpc/mm/hash64: Don't test for machine type to detect HEA special case")
Cc: stable@vger.kernel.org # v4.8+
Reported-by: Denis Kirjanov <kda@linux-powerpc.org>
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/mm/hash_utils_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 90480e23fd2c..44d3c3a38e3e 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -529,7 +529,7 @@ static bool might_have_hea(void)
 	 */
 #ifdef CONFIG_IBMEBUS
 	return !cpu_has_feature(CPU_FTR_ARCH_207S) &&
-		!firmware_has_feature(FW_FEATURE_SPLPAR);
+		firmware_has_feature(FW_FEATURE_SPLPAR);
 #else
 	return false;
 #endif
-- 
2.7.4

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