[lkml]   [2013]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[ 38/47] ARM: missing ->mmap_sem around find_vma() in swp_emulate.c
3.0-stable review patch.  If anyone has any objections, please let me know.


From: Al Viro <>

commit 7bf9b7bef881aac820bf1f2e9951a17b09bd7e04 upstream.

find_vma() is *not* safe when somebody else is removing vmas. Not just
the return value might get bogus just as you are getting it (this instance
doesn't try to dereference the resulting vma), the search itself can get
buggered in rather spectacular ways. IOW, ->mmap_sem really, really is
not optional here.

Signed-off-by: Al Viro <>
Signed-off-by: Russell King <>
Signed-off-by: Greg Kroah-Hartman <>

arch/arm/kernel/swp_emulate.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/arm/kernel/swp_emulate.c
+++ b/arch/arm/kernel/swp_emulate.c
@@ -108,10 +108,12 @@ static void set_segfault(struct pt_regs
siginfo_t info;

+ down_read(&current->mm->mmap_sem);
if (find_vma(current->mm, addr) == NULL)
info.si_code = SEGV_MAPERR;
info.si_code = SEGV_ACCERR;
+ up_read(&current->mm->mmap_sem);

info.si_signo = SIGSEGV;
info.si_errno = 0;

 \ /
  Last update: 2013-01-10 02:21    [W:0.173 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site