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Subject[PATCH] make inotify event handles use GFP_NOFS
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I think this is a bandaide to shut up lockdep.  I could either figure
out lockdep classes and figure out how to reclassify inotify locks since
I believe Nick is correct when he says inotify watches pin the inode in
core so memory pressure can't evict it. I don't want to do that as I
think the real fix is my next generation fsnotify which does zero
allocations under locks and so everything can be GFP_KERNEL. I'm
posting this as it is clearly safe and should fix the issue.

http://marc.info/?l=linux-kernel&m=123617147432377&w=2

includes a lockdep warning that shows while we are reclaiming FS memory
and inode may get evicted which generates an IN_IGNORED message. Half
of that code path already used GFP_NOFS but a second allocation to store
the filename was using GFP_KERNEL. As a precaution I also moved the
audit handle_event code path to use GFP_NOFS.

This is much the same as the precaution in f04b30de3c82528 which did
something similar.

Signed-off-by: Eric Paris <eparis@redhat.com>

---

fs/notify/inotify/inotify_user.c | 2 +-
kernel/auditfilter.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)


diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index bed766e..1634319 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
rem = 0;
}

- kevent->name = kmalloc(len + rem, GFP_KERNEL);
+ kevent->name = kmalloc(len + rem, GFP_NOFS);
if (unlikely(!kevent->name)) {
kmem_cache_free(event_cachep, kevent);
return NULL;
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index fbf24d1..a3fa2c0 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1028,7 +1028,7 @@ static void audit_update_watch(struct audit_parent *parent,

if (audit_enabled) {
struct audit_buffer *ab;
- ab = audit_log_start(NULL, GFP_KERNEL,
+ ab = audit_log_start(NULL, GFP_NOFS,
AUDIT_CONFIG_CHANGE);
audit_log_format(ab, "auid=%u ses=%u",
audit_get_loginuid(current),
@@ -1067,7 +1067,7 @@ static void audit_remove_parent_watches(struct audit_parent *parent)
e = container_of(r, struct audit_entry, rule);
if (audit_enabled) {
struct audit_buffer *ab;
- ab = audit_log_start(NULL, GFP_KERNEL,
+ ab = audit_log_start(NULL, GFP_NOFS,
AUDIT_CONFIG_CHANGE);
audit_log_format(ab, "auid=%u ses=%u",
audit_get_loginuid(current),



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