From 51f0471b12817e576e42ecea027177798a968db4 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Tue, 17 Apr 2018 23:29:07 -0700 Subject: perf/core: Fix bad use of igrab() commit 9511bce9fe8e5e6c0f923c09243a713eba560141 upstream As Miklos reported and suggested: "This pattern repeats two times in trace_uprobe.c and in kernel/events/core.c as well: ret = kern_path(filename, LOOKUP_FOLLOW, &path); if (ret) goto fail_address_parse; inode = igrab(d_inode(path.dentry)); path_put(&path); And it's wrong. You can only hold a reference to the inode if you have an active ref to the superblock as well (which is normally through path.mnt) or holding s_umount. This way unmounting the containing filesystem while the tracepoint is active will give you the "VFS: Busy inodes after unmount..." message and a crash when the inode is finally put. Solution: store path instead of inode." This patch fixes the issue in kernel/event/core.c. Reviewed-and-tested-by: Alexander Shishkin Reported-by: Miklos Szeredi Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: 375637bc5249 ("perf/core: Introduce address range filtering") Link: http://lkml.kernel.org/r/20180418062907.3210386-2-songliubraving@fb.com Signed-off-by: Ingo Molnar [sudip: Backported to 4.9: use file_inode()] Signed-off-by: Sudip Mukherjee Signed-off-by: Greg Kroah-Hartman --- include/linux/perf_event.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index ae8ecf821019..a7057b772612 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -475,7 +475,7 @@ struct pmu { */ struct perf_addr_filter { struct list_head entry; - struct inode *inode; + struct path path; unsigned long offset; unsigned long size; unsigned int range : 1, -- cgit v1.2.3