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Fix vmalloc_fault oops during lazy MMU (rhbz 914737)

This commit is contained in:
Josh Boyer 2013-02-26 08:14:54 -05:00
parent fa8ce41f27
commit a46911c9f8
2 changed files with 57 additions and 0 deletions
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9
kernel.spec
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@ -811,6 +811,9 @@ Patch22260: sock_diag-Fix-out-of-bounds-access-to-sock_diag_handlers.patch
#rhbz 903192
Patch22261: 0001-kmsg-Honor-dmesg_restrict-sysctl-on-dev-kmsg.patch
#rhbz 914737
Patch22262: x86-mm-Fix-vmalloc_fault-oops-during-lazy-MMU-updates.patch
Patch23000: silence-brcmsmac-warning.patch
#rhbz 812111
@ -1571,6 +1574,9 @@ ApplyPatch sock_diag-Fix-out-of-bounds-access-to-sock_diag_handlers.patch
#rhbz 903192
ApplyPatch 0001-kmsg-Honor-dmesg_restrict-sysctl-on-dev-kmsg.patch
#rhbz 914737
ApplyPatch x86-mm-Fix-vmalloc_fault-oops-during-lazy-MMU-updates.patch
# END OF PATCH APPLICATIONS
%endif
@ -2434,6 +2440,9 @@ fi
# ||----w |
# || ||
%changelog
* Tue Feb 26 2013 Josh Boyer <jwboyer@redhat.com>
- Fix vmalloc_fault oops during lazy MMU (rhbz 914737)
* Mon Feb 25 2013 Josh Boyer <jwboyer@redhat.com>
- Honor dmesg_restrict for /dev/kmsg (rhbz 903192)

48
x86-mm-Fix-vmalloc_fault-oops-during-lazy-MMU-updates.patch Normal file
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@ -0,0 +1,48 @@
From: Samu Kallio <>
Subject: [PATCH] x86: mm: Fix vmalloc_fault oops during lazy MMU updates.
Date: Sun, 17 Feb 2013 04:35:52 +0200
In paravirtualized x86_64 kernels, vmalloc_fault may cause an oops
when lazy MMU updates are enabled, because set_pgd effects are being
deferred.
One instance of this problem is during process mm cleanup with memory
cgroups enabled. The chain of events is as follows:
- zap_pte_range enables lazy MMU updates
- zap_pte_range eventually calls mem_cgroup_charge_statistics,
which accesses the vmalloc'd mem_cgroup per-cpu stat area
- vmalloc_fault is triggered which tries to sync the corresponding
PGD entry with set_pgd, but the update is deferred
- vmalloc_fault oopses due to a mismatch in the PUD entries
Calling arch_flush_lazy_mmu_mode immediately after set_pgd makes the
changes visible to the consistency checks.
Signed-off-by: Samu Kallio <samu.kallio@aberdeencloud.com>
---
arch/x86/mm/fault.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 8e13ecb..0a45298 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -378,10 +378,12 @@ static noinline __kprobes int vmalloc_fault(unsigned long address)
if (pgd_none(*pgd_ref))
return -1;
- if (pgd_none(*pgd))
+ if (pgd_none(*pgd)) {
set_pgd(pgd, *pgd_ref);
- else
+ arch_flush_lazy_mmu_mode();
+ } else {
BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
+ }
/*
* Below here mismatches are bugs because these lower tables
--
1.8.1.3