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Add patch to fix deadlock in ppc64 icswx code (rhbz 737984)

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This commit is contained in:
Josh Boyer 2011-09-14 16:12:02 -04:00
parent 1b241cbc21
commit 1830f9798f
2 changed files with 81 additions and 0 deletions
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7
kernel.spec
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@ -734,6 +734,8 @@ Patch13010: ibmveth-Fix-DMA-unmap-error.patch
Patch13011: ibmveth-Fix-issue-with-DMA-mapping-failure.patch
Patch13012: ibmveth-Checksum-offload-is-always-disabled.patch
Patch13013: powerpc-Fix-deadlock-in-icswx-code.patch
Patch20000: utrace.patch
# Flattened devicetree support
@ -1352,6 +1354,8 @@ ApplyPatch ibmveth-Fix-DMA-unmap-error.patch
ApplyPatch ibmveth-Fix-issue-with-DMA-mapping-failure.patch
ApplyPatch ibmveth-Checksum-offload-is-always-disabled.patch
ApplyPatch powerpc-Fix-deadlock-in-icswx-code.patch
# utrace.
ApplyPatch utrace.patch
@ -2063,6 +2067,9 @@ fi
# ||----w |
# || ||
%changelog
* Wed Sep 14 2011 Josh Boyer <jwboyer@redhat.com>
- Add patch to fix deadlock in ppc64 icswx (rhbz 737984)
* Wed Sep 14 2011 Neil Horman <nhorman@redhat.com>
- Enable CONFIG_IP_VS_IPV6 (bz 738194)

74
powerpc-Fix-deadlock-in-icswx-code.patch Normal file
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@ -0,0 +1,74 @@
From patchwork Wed Sep 14 19:43:15 2011
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: powerpc: Fix deadlock in icswx code
Date: Wed, 14 Sep 2011 09:43:15 -0000
From: Anton Blanchard <anton@samba.org>
X-Patchwork-Id: 114701
Message-Id: <20110915054315.5e5ae062@kryten>
To: benh@kernel.crashing.org, paulus@samba.org
Cc: linuxppc-dev@lists.ozlabs.org
The icswx code introduced an A-B B-A deadlock:
CPU0 CPU1
---- ----
lock(&anon_vma->mutex);
lock(&mm->mmap_sem);
lock(&anon_vma->mutex);
lock(&mm->mmap_sem);
Instead of using the mmap_sem to keep mm_users constant, take the
page table spinlock.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
---
diff --git a/arch/powerpc/mm/mmu_context_hash64.c b/arch/powerpc/mm/mmu_context_hash64.c
index 3bafc3d..4ff587e 100644
--- a/arch/powerpc/mm/mmu_context_hash64.c
+++ b/arch/powerpc/mm/mmu_context_hash64.c
@@ -136,8 +136,8 @@ int use_cop(unsigned long acop, struct mm_struct *mm)
if (!mm || !acop)
return -EINVAL;
- /* We need to make sure mm_users doesn't change */
- down_read(&mm->mmap_sem);
+ /* The page_table_lock ensures mm_users won't change under us */
+ spin_lock(&mm->page_table_lock);
spin_lock(mm->context.cop_lockp);
if (mm->context.cop_pid == COP_PID_NONE) {
@@ -164,7 +164,7 @@ int use_cop(unsigned long acop, struct mm_struct *mm)
out:
spin_unlock(mm->context.cop_lockp);
- up_read(&mm->mmap_sem);
+ spin_unlock(&mm->page_table_lock);
return ret;
}
@@ -185,8 +185,8 @@ void drop_cop(unsigned long acop, struct mm_struct *mm)
if (WARN_ON_ONCE(!mm))
return;
- /* We need to make sure mm_users doesn't change */
- down_read(&mm->mmap_sem);
+ /* The page_table_lock ensures mm_users won't change under us */
+ spin_lock(&mm->page_table_lock);
spin_lock(mm->context.cop_lockp);
mm->context.acop &= ~acop;
@@ -213,7 +213,7 @@ void drop_cop(unsigned long acop, struct mm_struct *mm)
}
spin_unlock(mm->context.cop_lockp);
- up_read(&mm->mmap_sem);
+ spin_unlock(&mm->page_table_lock);
}
EXPORT_SYMBOL_GPL(drop_cop);