Hi, greg k-h On 11-07-07 16:55, Greg KH wrote: > On Fri, Jun 24, 2011 at 03:02:08PM +0800, Wengang Wang wrote: > > mainline commit 2aa15890f3c191326678f1bd68af61ec6b8753ec > > > > mm: prevent concurrent unmap_mapping_range() on the same inode > > > > Michael Leun reported that running parallel opens on a fuse filesystem > > can trigger a "kernel BUG at mm/truncate.c:475" > > > > Gurudas Pai reported the same bug on NFS. > > > > The reason is, unmap_mapping_range() is not prepared for more than > > one concurrent invocation per inode. For example: > > > > thread1: going through a big range, stops in the middle of a vma and > > stores the restart address in vm_truncate_count. > > > > thread2: comes in with a small (e.g. single page) unmap request on > > the same vma, somewhere before restart_address, finds that the > > vma was already unmapped up to the restart address and happily > > returns without doing anything. > > > > Another scenario would be two big unmap requests, both having to > > restart the unmapping and each one setting vm_truncate_count to its > > own value. This could go on forever without any of them being able to > > finish. > > > > Truncate and hole punching already serialize with i_mutex. Other > > callers of unmap_mapping_range() do not, and it's difficult to get > > i_mutex protection for all callers. In particular ->d_revalidate(), > > which calls invalidate_inode_pages2_range() in fuse, may be called > > with or without i_mutex. > > > > This patch adds a new mutex to 'struct address_space' to prevent > > running multiple concurrent unmap_mapping_range() on the same mapping. > > > > [ We'll hopefully get rid of all this with the upcoming mm > > preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex > > lockbreak" patch in particular. But that is for 2.6.39 ] > > > > > > Adding this patch causes Kabi breakage. > > > > Signed-off-by: Miklos Szeredi <mszer...@suse.cz> > > Reported-by: Michael Leun <lkml20101...@newton.leun.net> > > Reported-by: Gurudas Pai <gurudas....@oracle.com> > > Tested-by: Gurudas Pai <gurudas....@oracle.com> > > Acked-by: Hugh Dickins <hu...@google.com> > > Cc: sta...@kernel.org > > Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> > > Signed-off-by: Wengang Wang <wen.gang.w...@oracle.com> > > As this patch showed up in 2.6.39, I'm confused as to what you wanted me > to do with it, so I've dropped it from my queue.
I hope this committed in 2.6.32 stable tree please. regards, wengang. _______________________________________________ stable mailing list stable@linux.kernel.org http://linux.kernel.org/mailman/listinfo/stable
