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powerpc/32: Fix hardlockup on vmap stack overflow

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Since the commit c118c7303a ("powerpc/32: Fix vmap stack - Do not
activate MMU before reading task struct") a vmap stack overflow
results in a hard lockup. This is because emergency_ctx is still
addressed with its virtual address allthough data MMU is not active
anymore at that time.

Fix it by using a physical address instead.

Fixes: c118c7303a ("powerpc/32: Fix vmap stack - Do not activate MMU before reading task struct")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ce30364fb7ccda489272af4a1612b6aa147e1d23.1637227521.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-11-18 10:39:53 +01:00 committed by Michael Ellerman
parent cf0b0e3712
commit 5bb60ea611
1 changed files with 3 additions and 3 deletions
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6
arch/powerpc/kernel/head_32.h
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@ -202,11 +202,11 @@ vmap_stack_overflow:
mfspr r1, SPRN_SPRG_THREAD
lwz r1, TASK_CPU - THREAD(r1)
slwi r1, r1, 3
addis r1, r1, emergency_ctx@ha
addis r1, r1, emergency_ctx-PAGE_OFFSET@ha
#else
lis r1, emergency_ctx@ha
lis r1, emergency_ctx-PAGE_OFFSET@ha
#endif
lwz r1, emergency_ctx@l(r1)
lwz r1, emergency_ctx-PAGE_OFFSET@l(r1)
addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE
EXCEPTION_PROLOG_2 0 vmap_stack_overflow
prepare_transfer_to_handler