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authorDave Wysochanski <dwysocha@redhat.com>2021-10-01 15:37:31 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2021-10-02 10:03:28 -0700
commit6e9bfdcf0a3b1c8126878c21adcfc343f89d4a6a (patch)
tree5ecba2769543440629b34ce3a67c64c74f996ae5
parentcdc1e6e225e3256d56dc6648411630e71d7c776b (diff)
cachefiles: Fix oops in trace_cachefiles_mark_buried due to NULL object
In cachefiles_mark_object_buried, the dentry in question may not have an owner, and thus our cachefiles_object pointer may be NULL when calling the tracepoint, in which case we will also not have a valid debug_id to print in the tracepoint. Check for NULL object in the tracepoint and if so, just set debug_id to MAX_UINT as was done in 2908f5e101e3 ("fscache: Add a cookie debug ID and use that in traces"). This fixes the following oops: FS-Cache: Cache "mycache" added (type cachefiles) CacheFiles: File cache on vdc registered ... Workqueue: fscache_object fscache_object_work_func [fscache] RIP: 0010:trace_event_raw_event_cachefiles_mark_buried+0x4e/0xa0 [cachefiles] .... Call Trace: cachefiles_mark_object_buried+0xa5/0xb0 [cachefiles] cachefiles_bury_object+0x270/0x430 [cachefiles] cachefiles_walk_to_object+0x195/0x9c0 [cachefiles] cachefiles_lookup_object+0x5a/0xc0 [cachefiles] fscache_look_up_object+0xd7/0x160 [fscache] fscache_object_work_func+0xb2/0x340 [fscache] process_one_work+0x1f1/0x390 worker_thread+0x53/0x3e0 kthread+0x127/0x150 Fixes: 2908f5e101e3 ("fscache: Add a cookie debug ID and use that in traces") Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-cachefs@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/trace/events/cachefiles.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 9a448fe9355d..695bfdbfdcad 100644
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -305,7 +305,7 @@ TRACE_EVENT(cachefiles_mark_buried,
),
TP_fast_assign(
- __entry->obj = obj->fscache.debug_id;
+ __entry->obj = obj ? obj->fscache.debug_id : UINT_MAX;
__entry->de = de;
__entry->why = why;
),