The patch titled
do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails
has been removed from the -mm tree. Its filename was
do_generic_file_read-s-eintr-eio-if-lock_page_killable-fails.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails
From: Oleg Nesterov <oleg@xxxxxxxxxx>
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 <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Matthew Wilcox <matthew@xxxxxx>
Cc: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff -puN mm/filemap.c~do_generic_file_read-s-eintr-eio-if-lock_page_killable-fails mm/filemap.c
--- a/mm/filemap.c~do_generic_file_read-s-eintr-eio-if-lock_page_killable-fails
+++ a/mm/filemap.c
@@ -1000,8 +1000,9 @@ page_ok:
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;
/* Did it get truncated before we got the lock? */
if (!page->mapping) {
@@ -1029,8 +1030,9 @@ readpage:
}
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) {
/*
@@ -1042,15 +1044,14 @@ readpage:
}
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;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
introduce-pf_kthread-flag.patch
kill-pf_borrowed_mm-in-favour-of-pf_kthread.patch
coredump-zap_threads-must-skip-kernel-threads.patch
posix-timers-timer_delete-remove-the-bogus-it_process-=-null-check.patch
posix-timers-release_posix_timer-kill-the-bogus-put_task_struct-it_process.patch
signals-collect_signal-remove-the-unneeded-sigismember-check.patch
signals-collect_signal-simplify-the-still_pending-logic.patch
signals-change-collect_signal-to-return-void.patch
__exit_signal-dont-take-rcu-lock.patch
signals-dequeue_signal-dont-check-signal_group_exit-when-setting-signal_stop_dequeued.patch
signals-do_signal_stop-kill-the-signal_unkillable-check.patch
coredump-zap_threads-comments-use-while_each_thread.patch
distinct-tgid-tid-i-o-statistics.patch
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