From: Konstantin Khlebnikov <[email protected]> [ Upstream commit ad80b932c57d85fd6377f97f359b025baf179a87 ]
Do not remain stuck forever if something goes wrong. Using a killable lock permits cleanup of stuck tasks and simplifies investigation. Link: http://lkml.kernel.org/r/156007493638.3335.4872164955523928492.stgit@buzz Signed-off-by: Konstantin Khlebnikov <[email protected]> Reviewed-by: Roman Gushchin <[email protected]> Reviewed-by: Cyrill Gorcunov <[email protected]> Reviewed-by: Kirill Tkhai <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Al Viro <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Michal Koutný <[email protected]> Cc: Oleg Nesterov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- fs/proc/task_mmu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 4d9a8e72d91f..1d9c63cd8a3c 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1543,7 +1543,9 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, /* overflow ? */ if (end < start_vaddr || end > end_vaddr) end = end_vaddr; - down_read(&mm->mmap_sem); + ret = down_read_killable(&mm->mmap_sem); + if (ret) + goto out_free; ret = walk_page_range(start_vaddr, end, &pagemap_walk); up_read(&mm->mmap_sem); start_vaddr = end; -- 2.20.1
