| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.4 130/134] s390: disable preemption when switching to nodat stack with CALL_ON_STACK | Date | Wed, 11 Dec 2019 10:11:46 -0500 |
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From: Vasily Gorbik <gor@linux.ibm.com>
[ Upstream commit 7f28dad395243c5026d649136823bbc40029a828 ]
Make sure preemption is disabled when temporary switching to nodat stack with CALL_ON_STACK helper, because nodat stack is per cpu.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/s390/kernel/machine_kexec.c | 2 ++ arch/s390/mm/maccess.c | 12 +++++++++--- 2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c index 444a19125a815..dcaadceaf6efc 100644 --- a/arch/s390/kernel/machine_kexec.c +++ b/arch/s390/kernel/machine_kexec.c @@ -164,7 +164,9 @@ static bool kdump_csum_valid(struct kimage *image) #ifdef CONFIG_CRASH_DUMP int rc; + preempt_disable(); rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image); + preempt_enable(); return rc == 0; #else return false; diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 1864a8bb9622f..88d5fcf67a2f1 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -115,9 +115,15 @@ static unsigned long _memcpy_real(unsigned long dest, unsigned long src, */ int memcpy_real(void *dest, void *src, size_t count) { - if (S390_lowcore.nodat_stack != 0) - return CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack, - 3, dest, src, count); + int rc; + + if (S390_lowcore.nodat_stack != 0) { + preempt_disable(); + rc = CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack, 3, + dest, src, count); + preempt_enable(); + return rc; + } /* * This is a really early memcpy_real call, the stacks are * not set up yet. Just call _memcpy_real on the early boot -- 2.20.1
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