Messages in this thread | | | Date | Tue, 29 Nov 2022 09:56:20 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] mm/writeback: fix dereferencing NULL mapping->host |
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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; > ), >
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