From 85462323555dda749f1c5373a8d72679464c968d Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 8 Jun 2008 21:20:43 +0400 Subject: [PATCH] do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails If lock_page_killable() fails because the task was killed by SIGKILL or any other fatal signal, do_generic_file_read() returns -EIO. This seems to be OK, because in fact the userspace won't see this error, the task will dequeue SIGKILL and exit. However, /sbin/init is different, it will dequeue SIGKILL, ignore it, and return to the user-space with the bogus -EIO. Change the code to return the error code from lock_page_killable(), -EINTR. This doesn't fix the bug, but perhaps makes sense anyway. Imho, with this change the code looks a bit more logical, and the "good" init should handle the spurious EINTR or short read. Afaics we can also change lock_page_killable() to return -ERESTARTNOINTR, but this can't prevent the short reads. Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar --- mm/filemap.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 876bc595d0f8..494ff20b6cfa 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1100,8 +1100,9 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, page_not_up_to_date: /* Get exclusive access to the page ... */ - if (lock_page_killable(page)) - goto readpage_eio; + error = lock_page_killable(page); + if (unlikely(error)) + goto readpage_error; page_not_up_to_date_locked: /* Did it get truncated before we got the lock? */ @@ -1130,8 +1131,9 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, } if (!PageUptodate(page)) { - if (lock_page_killable(page)) - goto readpage_eio; + error = lock_page_killable(page); + if (unlikely(error)) + goto readpage_error; if (!PageUptodate(page)) { if (page->mapping == NULL) { /* @@ -1143,15 +1145,14 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, } unlock_page(page); shrink_readahead_size_eio(filp, ra); - goto readpage_eio; + error = -EIO; + goto readpage_error; } unlock_page(page); } goto page_ok; -readpage_eio: - error = -EIO; readpage_error: /* UHHUH! A synchronous read error occurred. Report it */ desc->error = error;