Messages in this thread | | | From | Andrew Yang <> | Subject | Re: [PATCH v2] mm/writeback: fix dereferencing NULL mapping->host | Date | Wed, 30 Nov 2022 16:23:03 +0800 |
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On Tue, 2022-11-29 at 09:56 -0500, Steven Rostedt wrote: > On Tue, 29 Nov 2022 11:32:59 +0800 > Andrew Yang <andrew.yang@mediatek.com> wrote: > > > From: "andrew.yang" <andrew.yang@mediatek.com> > > > > Check before dereferencing mapping->host > > > > Signed-off-by: andrew.yang <andrew.yang@mediatek.com> > > --- > > include/trace/events/writeback.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/trace/events/writeback.h > > b/include/trace/events/writeback.h > > index 86b2a82da546..56f6e114d3ed 100644 > > --- a/include/trace/events/writeback.h > > +++ b/include/trace/events/writeback.h > > @@ -68,7 +68,7 @@ DECLARE_EVENT_CLASS(writeback_folio_template, > > strscpy_pad(__entry->name, > > bdi_dev_name(mapping ? > > inode_to_bdi(mapping->host) : > > NULL), 32); > > - __entry->ino = mapping ? mapping->host->i_ino : 0; > > + __entry->ino = mapping && mapping->host ? mapping- > > >host->i_ino : 0; > > I hate remembering precedence. Can we add parenthesis around this to > be > clear? > > __entry->ino = (mapping && mapping->host) ? mapping- > >host->i_ino : 0; > > Thanks, > > -- Steve > > > > __entry->index = folio->index; > > ), > > > > Sure, that's a good suggestion
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