From: Sasha Levin <sashal@kernel•org>
To: linux-kernel@vger•kernel.org, stable@vger•kernel.org
Cc: Sasha Levin <sashal@kernel•org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com>,
linuxppc-dev@lists•ozlabs.org
Subject: [PATCH AUTOSEL 4.19 557/671] powerpc/mm/mce: Keep irqs disabled during lockless page table walk
Date: Thu, 16 Jan 2020 12:03:15 -0500 [thread overview]
Message-ID: <20200116170509.12787-294-sashal@kernel.org> (raw)
In-Reply-To: <20200116170509.12787-1-sashal@kernel.org>
From: "Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com>
[ Upstream commit d9101bfa6adc831bda8836c4d774820553c14942 ]
__find_linux_mm_pte() returns a page table entry pointer after walking
the page table without holding locks. To make it safe against a THP
split and/or collapse, we disable interrupts around the lockless page
table walk. However we need to keep interrupts disabled as long as we
use the page table entry pointer that is returned.
Fix addr_to_pfn() to do that.
Fixes: ba41e1e1ccb9 ("powerpc/mce: Hookup derror (load/store) UE errors")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux•ibm.com>
[mpe: Rearrange code slightly and tweak change log wording]
Signed-off-by: Michael Ellerman <mpe@ellerman•id.au>
Link: https://lore.kernel.org/r/20190918145328.28602-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel•org>
---
arch/powerpc/kernel/mce_power.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index 37a110b8e7e1..ecb375040637 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -40,7 +40,7 @@ static unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
{
pte_t *ptep;
unsigned int shift;
- unsigned long flags;
+ unsigned long pfn, flags;
struct mm_struct *mm;
if (user_mode(regs))
@@ -50,18 +50,22 @@ static unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
local_irq_save(flags);
ptep = __find_linux_pte(mm->pgd, addr, NULL, &shift);
- local_irq_restore(flags);
- if (!ptep || pte_special(*ptep))
- return ULONG_MAX;
+ if (!ptep || pte_special(*ptep)) {
+ pfn = ULONG_MAX;
+ goto out;
+ }
- if (shift > PAGE_SHIFT) {
+ if (shift <= PAGE_SHIFT)
+ pfn = pte_pfn(*ptep);
+ else {
unsigned long rpnmask = (1ul << shift) - PAGE_SIZE;
-
- return pte_pfn(__pte(pte_val(*ptep) | (addr & rpnmask)));
+ pfn = pte_pfn(__pte(pte_val(*ptep) | (addr & rpnmask)));
}
- return pte_pfn(*ptep);
+out:
+ local_irq_restore(flags);
+ return pfn;
}
/* flush SLBs and reload */
--
2.20.1
next prev parent reply other threads:[~2020-01-16 18:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200116170509.12787-1-sashal@kernel.org>
2020-01-16 16:58 ` [PATCH AUTOSEL 4.19 273/671] soc/fsl/qe: Fix an error code in qe_pin_request() Sasha Levin
2020-01-16 16:59 ` [PATCH AUTOSEL 4.19 304/671] powerpc: vdso: Make vdso32 installation conditional in vdso_install Sasha Levin
2020-01-16 16:59 ` [PATCH AUTOSEL 4.19 319/671] KVM: PPC: Book3S HV: Fix lockdep warning when entering the guest Sasha Levin
2020-01-16 17:00 ` [PATCH AUTOSEL 4.19 415/671] powerpc/cacheinfo: add cacheinfo_teardown, cacheinfo_rebuild Sasha Levin
2020-01-16 17:00 ` [PATCH AUTOSEL 4.19 416/671] powerpc/pseries/mobility: rebuild cacheinfo hierarchy post-migration Sasha Levin
2020-01-16 17:01 ` [PATCH AUTOSEL 4.19 432/671] perf/ioctl: Add check for the sample_period value Sasha Levin
2020-01-16 17:01 ` [PATCH AUTOSEL 4.19 475/671] ALSA: aoa: onyx: always initialize register read value Sasha Levin
2020-01-16 17:02 ` [PATCH AUTOSEL 4.19 499/671] powerpc/64s/radix: Fix memory hot-unplug page table split Sasha Levin
2020-01-16 17:03 ` Sasha Levin [this message]
2020-01-16 17:04 ` [PATCH AUTOSEL 4.19 655/671] powerpc/powernv: Disable native PCIe port management Sasha Levin
2020-01-16 17:05 ` [PATCH AUTOSEL 4.19 665/671] powerpc/archrandom: fix arch_get_random_seed_int() Sasha Levin
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