diff options
Diffstat (limited to 'sys-kernel/gentoo-sources/files/gentoo-sources-2.4.77666.patch')
| -rw-r--r-- | sys-kernel/gentoo-sources/files/gentoo-sources-2.4.77666.patch | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/sys-kernel/gentoo-sources/files/gentoo-sources-2.4.77666.patch b/sys-kernel/gentoo-sources/files/gentoo-sources-2.4.77666.patch new file mode 100644 index 000000000000..6b687788f912 --- /dev/null +++ b/sys-kernel/gentoo-sources/files/gentoo-sources-2.4.77666.patch @@ -0,0 +1,44 @@ +# This is a BitKeeper generated diff -Nru style patch. +# +# ChangeSet +# 2005/01/12 09:14:50-02:00 marcelo.tosatti@cyclades.com +# [PATCH] Fix expand_stack() SMP race +# +# Description: Fix expand_stack() SMP race +# +# Two threads sharing the same VMA can race in expand_stack, resulting in incorrect VMA +# size accounting and possibly a "uncovered-by-VMA" pte leak. +# +# Fix is to check if the stack has already been expanded after acquiring a lock which +# guarantees exclusivity (page_table_lock in v2.4 and vma_anon lock in v2.6). +# +# include/linux/mm.h +# 2005/01/07 14:51:21-02:00 marcelo.tosatti@cyclades.com +10 -3 +# Fix expand_stack() SMP race +# +diff -Nru a/include/linux/mm.h b/include/linux/mm.h +--- a/include/linux/mm.h 2005-01-13 04:59:30 -08:00 ++++ b/include/linux/mm.h 2005-01-13 04:59:30 -08:00 +@@ -648,12 +648,19 @@ + unsigned long grow; + + /* +- * vma->vm_start/vm_end cannot change under us because the caller is required +- * to hold the mmap_sem in write mode. We need to get the spinlock only +- * before relocating the vma range ourself. ++ * vma->vm_start/vm_end cannot change under us because the caller ++ * is required to hold the mmap_sem in read mode. We need the ++ * page_table_lock lock to serialize against concurrent expand_stacks. + */ + address &= PAGE_MASK; + spin_lock(&vma->vm_mm->page_table_lock); ++ ++ /* already expanded while we were spinning? */ ++ if (vma->vm_start <= address) { ++ spin_unlock(&vma->vm_mm->page_table_lock); ++ return 0; ++ } ++ + grow = (vma->vm_start - address) >> PAGE_SHIFT; + if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur || + ((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->rlim[RLIMIT_AS].rlim_cur) { |