2013/5/14 Raul Xiong <raulxiong@xxxxxxxxx> > > 2013/5/14 Neil Zhang <glacier1980@xxxxxxxxx>: > > 2013/5/14 Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>: > >> On Wed, May 01, 2013 at 09:56:13AM -0400, Robert Love wrote: > >>> Don't acquire ashmem_mutex in ashmem_shrink if we've somehow recursed > >>> into the > >>> shrinker code from within ashmem. Just bail out, avoiding a deadlock. > >>> This is > >>> fine, as ashmem cache pruning is advisory anyhow. > >>> > >>> Signed-off-by: Robert Love <rlove@xxxxxxxxxx> > >>> --- > >>> drivers/staging/android/ashmem.c | 6 +++++- > >>> 1 file changed, 5 insertions(+), 1 deletion(-) > >> > >> Based on Andrew's review comments, I'll drop this from my queue and wait > >> for a "better" fix for this. > >> > >> thanks, > >> > >> greg k-h > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > >> the body of a message to majordomo@xxxxxxxxxxxxxxx > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> Please read the FAQ at http://www.tux.org/lkml/ > > > > We found the similar issue these days. > > Add RaulXiong to paste the call stack. > > > > Best Regards, > > Neil Zhang > > Hi all, > I just encountered this deadlock during some stress test and it can be > described clearly by below function stack. Please check and suggest a > formal fix for it. > > [<c05d3370>] (__schedule) from [<c05d3818>] > [<c05d3818>] (schedule_preempt_disabled) from [<c05d2578>] > [<c05d2578>] (__mutex_lock_slowpath) from [<c05d263c>] > [<c05d263c>] (mutex_lock) from [<c0441dd8>] > [<c0441dd8>] (ashmem_shrink) from [<c01ae00c>] > [<c01ae00c>] (shrink_slab) from [<c01b0ec8>] > [<c01b0ec8>] (try_to_free_pages) from [<c01a65ec>] > [<c01a65ec>] (__alloc_pages_nodemask) from [<c01d0414>] > [<c01d0414>] (new_slab) from [<c05cf3a0>] > [<c05cf3a0>] (__slab_alloc.isra.46.constprop.52) from [<c01d08cc>] > [<c01d08cc>] (kmem_cache_alloc) from [<c01b1f6c>] > [<c01b1f6c>] (shmem_alloc_inode) from [<c01e8d18>] > [<c01e8d18>] (alloc_inode) from [<c01ea3c4>] > [<c01ea3c4>] (new_inode_pseudo) from [<c01ea404>] > [<c01ea404>] (new_inode) from [<c01b157c>] > [<c01b157c>] (shmem_get_inode) from [<c01b3eac>] > [<c01b3eac>] (shmem_file_setup) from [<c0441d1c>] > [<c0441d1c>] (ashmem_mmap) from [<c01c1908>] > [<c01c1908>] (mmap_region) from [<c01c1eac>] > [<c01c1eac>] (sys_mmap_pgoff) from [<c0112d80>] > > Thanks, > Raul Xiong Hi Andrew, Greg, Any feedback? The issue happens in such sequence: ashmem_mmap acquired ashmem_mutex --> ashmem_mutex:shmem_file_setup called kmem_cache_alloc --> shrink due to low memory --> ashmem_shrink tries to acquire the same ashmem_mutex -- it blocks here. I think this reports the bug clearly. Please have a look. Thanks, Raul Xiong -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
