another 2.6.23 patch

diff --git a/queue-2.6.23/remove-broken-ptrace-special-case-code-from-file-mapping.patch b/queue-2.6.23/remove-broken-ptrace-special-case-code-from-file-mapping.patch
new file mode 100644 (file)
index 0000000..290f3d4
--- /dev/null
+++ b/queue-2.6.23/remove-broken-ptrace-special-case-code-from-file-mapping.patch
@@ -0,0 +1,68 @@
+From 5307cc1aa53850f017c8053db034cf950b670ac9 Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@woody.linux-foundation.org>
+Date: Wed, 31 Oct 2007 09:19:46 -0700
+Subject: Remove broken ptrace() special-case code from file mapping
+
+The kernel has for random historical reasons allowed ptrace() accesses
+to access (and insert) pages into the page cache above the size of the
+file.
+
+However, Nick broke that by mistake when doing the new fault handling in
+commit 54cb8821de07f2ffcd28c380ce9b93d5784b40d7 ("mm: merge populate and
+nopage into fault (fixes nonlinear)".  The breakage caused a hang with
+gdb when trying to access the invalid page.
+
+The ptrace "feature" really isn't worth resurrecting, since it really is
+wrong both from a portability _and_ from an internal page cache validity
+standpoint.  So this removes those old broken remnants, and fixes the
+ptrace() hang in the process.
+
+Noticed and bisected by Duane Griffin, who also supplied a test-case
+(quoth Nick: "Well that's probably the best bug report I've ever had,
+thanks Duane!").
+
+Cc: Duane Griffin <duaneg@dghda.com>
+Acked-by: Nick Piggin <npiggin@suse.de>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ mm/filemap.c |   13 ++-----------
+ 1 file changed, 2 insertions(+), 11 deletions(-)
+
+--- a/mm/filemap.c
++++ b/mm/filemap.c
+@@ -1312,7 +1312,7 @@ int filemap_fault(struct vm_area_struct 
+ 
+       size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       if (vmf->pgoff >= size)
+-              goto outside_data_content;
++              return VM_FAULT_SIGBUS;
+ 
+       /* If we don't want any read-ahead, don't bother */
+       if (VM_RandomReadHint(vma))
+@@ -1389,7 +1389,7 @@ retry_find:
+       if (unlikely(vmf->pgoff >= size)) {
+               unlock_page(page);
+               page_cache_release(page);
+-              goto outside_data_content;
++              return VM_FAULT_SIGBUS;
+       }
+ 
+       /*
+@@ -1400,15 +1400,6 @@ retry_find:
+       vmf->page = page;
+       return ret | VM_FAULT_LOCKED;
+ 
+-outside_data_content:
+-      /*
+-       * An external ptracer can access pages that normally aren't
+-       * accessible..
+-       */
+-      if (vma->vm_mm == current->mm)
+-              return VM_FAULT_SIGBUS;
+-
+-      /* Fall through to the non-read-ahead case */
+ no_cached_page:
+       /*
+        * We're only likely to ever get here if MADV_RANDOM is in

diff --git a/queue-2.6.23/series b/queue-2.6.23/series
index 358bd8276e985cbf892ee0603f46143432355129..7501c7c12085a559e5b6043a4a1944fd69a04f18 100644 (file)
--- a/queue-2.6.23/series
+++ b/queue-2.6.23/series
@@ -10,3 +10,4 @@ hwmon-lm87-fix-a-division-by-zero.patch
 hwmon-lm87-disable-vid-when-it-should-be.patch
 add-get_unaligned-to-ieee80211_get_radiotap_len.patch
 mac80211-improve-sanity-checks-on-injected-packets.patch
+remove-broken-ptrace-special-case-code-from-file-mapping.patch