| Message ID | 20200419194529.4872-8-mcgrof@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: fix blktrace debugfs use after free | expand |
On 4/19/20 12:45 PM, Luis Chamberlain wrote: > +static int blk_trace_create_debugfs_files(struct blk_user_trace_setup *buts, > + struct dentry *dir, > + struct blk_trace *bt) > +{ > + int ret = -EIO; > + > + bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, > + &blk_dropped_fops); > + > + bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); > + > + bt->rchan = relay_open("trace", dir, buts->buf_size, > + buts->buf_nr, &blk_relay_callbacks, bt); > + if (!bt->rchan) > + return ret; > + > + return 0; > +} How about adding IS_ERR() checks for the debugfs_create_file() return values? Thanks, Bart.
On Sun, Apr 19, 2020 at 03:55:15PM -0700, Bart Van Assche wrote: > On 4/19/20 12:45 PM, Luis Chamberlain wrote: > > +static int blk_trace_create_debugfs_files(struct blk_user_trace_setup *buts, > > + struct dentry *dir, > > + struct blk_trace *bt) > > +{ > > + int ret = -EIO; > > + > > + bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, > > + &blk_dropped_fops); > > + > > + bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); > > + > > + bt->rchan = relay_open("trace", dir, buts->buf_size, > > + buts->buf_nr, &blk_relay_callbacks, bt); > > + if (!bt->rchan) > > + return ret; > > + > > + return 0; > > +} > > How about adding IS_ERR() checks for the debugfs_create_file() return > values? No, please no, I have been removing all of that nonsense from the kernel for the past 3-4 releases. You should never care about the return value from that call, just save it off and move on. as it is, this is correct. greg k-h
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 909db597b551..9cc0153849c3 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -548,6 +548,25 @@ static struct dentry *blk_trace_debugfs_dir(struct blk_user_trace_setup *buts, return bt->dir; } +static int blk_trace_create_debugfs_files(struct blk_user_trace_setup *buts, + struct dentry *dir, + struct blk_trace *bt) +{ + int ret = -EIO; + + bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, + &blk_dropped_fops); + + bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); + + bt->rchan = relay_open("trace", dir, buts->buf_size, + buts->buf_nr, &blk_relay_callbacks, bt); + if (!bt->rchan) + return ret; + + return 0; +} + /* * Setup everything required to start tracing */ @@ -597,15 +616,8 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, atomic_set(&bt->dropped, 0); INIT_LIST_HEAD(&bt->running_list); - ret = -EIO; - bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, - &blk_dropped_fops); - - bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); - - bt->rchan = relay_open("trace", dir, buts->buf_size, - buts->buf_nr, &blk_relay_callbacks, bt); - if (!bt->rchan) + ret = blk_trace_create_debugfs_files(buts, dir, bt); + if (ret) goto err; bt->act_mask = buts->act_mask;
Move creating the blktrace debugfs files into its own function. We'll expand on this later. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> --- kernel/trace/blktrace.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-)