diff options
author | Song Liu <songliubraving@fb.com> | 2018-04-17 23:29:07 -0700 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2018-05-25 08:11:10 +0200 |
commit | 9511bce9fe8e5e6c0f923c09243a713eba560141 (patch) | |
tree | ec6fcbc749ef80e7d8bd941fe261031f1cf95f2b /kernel/events | |
parent | a1150c202207cc8501bebc45b63c264f91959260 (diff) | |
download | op-kernel-dev-9511bce9fe8e5e6c0f923c09243a713eba560141.zip op-kernel-dev-9511bce9fe8e5e6c0f923c09243a713eba560141.tar.gz |
perf/core: Fix bad use of igrab()
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 <alexander.shishkin@linux.intel.com>
Reported-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
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 <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r-- | kernel/events/core.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index ce6aa5f..24dea13 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6668,7 +6668,7 @@ static void perf_event_addr_filters_exec(struct perf_event *event, void *data) raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { - if (filter->inode) { + if (filter->path.dentry) { event->addr_filters_offs[count] = 0; restart++; } @@ -7333,7 +7333,7 @@ static bool perf_addr_filter_match(struct perf_addr_filter *filter, struct file *file, unsigned long offset, unsigned long size) { - if (filter->inode != file_inode(file)) + if (d_inode(filter->path.dentry) != file_inode(file)) return false; if (filter->offset > offset + size) @@ -8686,8 +8686,7 @@ static void free_filters_list(struct list_head *filters) struct perf_addr_filter *filter, *iter; list_for_each_entry_safe(filter, iter, filters, entry) { - if (filter->inode) - iput(filter->inode); + path_put(&filter->path); list_del(&filter->entry); kfree(filter); } @@ -8784,7 +8783,7 @@ static void perf_event_addr_filters_apply(struct perf_event *event) * Adjust base offset if the filter is associated to a binary * that needs to be mapped: */ - if (filter->inode) + if (filter->path.dentry) event->addr_filters_offs[count] = perf_addr_filter_apply(filter, mm); @@ -8858,7 +8857,6 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr, { struct perf_addr_filter *filter = NULL; char *start, *orig, *filename = NULL; - struct path path; substring_t args[MAX_OPT_ARGS]; int state = IF_STATE_ACTION, token; unsigned int kernel = 0; @@ -8971,19 +8969,18 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr, goto fail_free_name; /* look up the path and grab its inode */ - ret = kern_path(filename, LOOKUP_FOLLOW, &path); + ret = kern_path(filename, LOOKUP_FOLLOW, + &filter->path); if (ret) goto fail_free_name; - filter->inode = igrab(d_inode(path.dentry)); - path_put(&path); kfree(filename); filename = NULL; ret = -EINVAL; - if (!filter->inode || - !S_ISREG(filter->inode->i_mode)) - /* free_filters_list() will iput() */ + if (!filter->path.dentry || + !S_ISREG(d_inode(filter->path.dentry) + ->i_mode)) goto fail; event->addr_filters.nr_file_filters++; |