diff options
| author | Graf Yang <graf.yang@analog.com> | 2010-01-13 06:09:34 +0000 |
|---|---|---|
| committer | Mike Frysinger <vapier@gentoo.org> | 2010-03-09 00:30:49 -0500 |
| commit | c6669c223a409199a45bb8f31a2e160ee26d19cc (patch) | |
| tree | cb46eb31a6ed699ce7ed31e874e965a38f987bd5 /arch/blackfin/kernel/traps.c | |
| parent | 7e1082b7dbb60081b157d82106da33686cb9ea91 (diff) | |
Blackfin: fix up mm locking in address dumping
The locking code in the address dumper needs to grab the mm's mmap_sem
so that other CPUs do not get an inconsistent view. On UP systems this
really wasn't a problem, but it is easy to trigger a race on SMP systems
when another CPU removes a mapping.
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/kernel/traps.c')
| -rw-r--r-- | arch/blackfin/kernel/traps.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c index 870d74b1b40..85766805b03 100644 --- a/arch/blackfin/kernel/traps.c +++ b/arch/blackfin/kernel/traps.c @@ -138,6 +138,12 @@ static void decode_address(char *buf, unsigned long address) if (!mm) continue; + if (!down_read_trylock(&mm->mmap_sem)) { + if (!in_atomic) + mmput(mm); + continue; + } + for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { struct vm_area_struct *vma; @@ -177,6 +183,7 @@ static void decode_address(char *buf, unsigned long address) sprintf(buf, "[ %s vma:0x%lx-0x%lx]", name, vma->vm_start, vma->vm_end); + up_read(&mm->mmap_sem); if (!in_atomic) mmput(mm); @@ -186,11 +193,16 @@ static void decode_address(char *buf, unsigned long address) goto done; } } + + up_read(&mm->mmap_sem); if (!in_atomic) mmput(mm); } - /* we were unable to find this address anywhere */ + /* + * we were unable to find this address anywhere, + * or some MMs were skipped because they were in use. + */ sprintf(buf, "/* kernel dynamic memory */"); done: |