fb735ab12ebe7964714c637bcb64163646cd347 parent 16a100190d39592d1d56ff5a0b978b20288c3427 author Hugh Dickins 1175156438 -0700 committer Linus Torvalds 1175181746 -0700 [PATCH] holepunch: fix mmap_sem i_mutex deadlock sys_madvise has down_write of mmap_sem, then madvise_remove calls vmtruncate_range which takes i_mutex and i_alloc_sem: no, we can easily devise deadlocks from that ordering. madvise_remove drop mmap_sem while calling vmtruncate_range: luckily, since madvise_remove doesn't split or merge vmas, it's easy to handle this case with a NULL prev, without restructuring sys_madvise. (Though sad to retake mmap_sem when it's unlikely to be needed, and certainly down_read is sufficient for MADV_REMOVE, unlike the other madvices.) Signed-off-by: Hugh Dickins Cc: Miklos Szeredi Cc: Badari Pulavarty Cc: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds £d|.šZx