Le 01/08/2021 à 03:21, Finn Thain a écrit :
On Sat, 31 Jul 2021, Christophe Leroy wrote:
Stan Johnson contacted me about a regression in mainline that he
observed on his G3 Powerbooks. Using 'git bisect' we determined that
this patch was the cause of the regression, i.e. commit 4c0104a83fc3
("powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE").
When testing 4c0104a83fc and all subsequent builds, various user
processes were liable to segfault. Here is the console log that Stan
provided:
Hi, i will be able to look at that more in details next week, however I
have a few preliminary qurstions.
Can you reliabily reproduce the problem with the said commit, and can
you reliabily run without problem with the parent commit ?
Yes and yes. (I already asked Stan to establish those things before I
contacted the list.)
I think I found the problem with that commit. Can you retry with the
following change:
diff --git a/arch/powerpc/kernel/head_book3s_32.S
b/arch/powerpc/kernel/head_book3s_32.S
index 0a3d7d4a9ec4..a294103a91a1 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -299,7 +299,7 @@ ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HPTE_TABLE)
EXCEPTION_PROLOG_1
EXCEPTION_PROLOG_2 0x300 DataAccess handle_dar_dsisr=1
prepare_transfer_to_handler
- lwz r5, _DSISR(r11)
+ lwz r5, _DSISR(r1)
andis. r0, r5, DSISR_DABRMATCH@h
bne- 1f
bl do_page_fault
---
Thanks
Christophe
