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[37.188.147.249]) by smtp.gmail.com with ESMTPSA id vl21-20020a17090730d500b00a235a62516asm6285729ejb.57.2023.12.26.23.35.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Dec 2023 23:35:25 -0800 (PST) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Wed, 27 Dec 2023 08:34:57 +0100 To: Edward Adam Davis , Mark Rutland Cc: syzbot+07144c543a5c002c7305@syzkaller.appspotmail.com, acme@kernel.org, adrian.hunter@intel.com, alexander.shishkin@linux.intel.com, irogers@google.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com, namhyung@kernel.org, netdev@vger.kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, xrivendell7@gmail.com Subject: Re: [PATCH] perf: fix WARNING in perf_event_open Message-ID: References: <0000000000005b23dc060d58ee7a@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Dec 26, 2023 at 03:25:15PM +0800, Edward Adam Davis wrote: > The new version of __perf_event_read_size() only has a read action and does not > require a mutex, so the mutex assertion in the original loop is removed. > > Fixes: 382c27f4ed28 ("perf: Fix perf_event_validate_size()") > Reported-and-tested-by: syzbot+07144c543a5c002c7305@syzkaller.appspotmail.com > Signed-off-by: Edward Adam Davis hi, Mark suggested another fix earlier [1], but I haven't seen the formal patch yet jirka [1] https://lore.kernel.org/linux-perf-users/ZXwubNIxKH9s7DWt@FVFF77S0Q05N/ > --- > kernel/events/core.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 9efd0d7775e7..e71e61b46416 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -1924,6 +1924,10 @@ static void perf_event__id_header_size(struct perf_event *event) > event->id_header_size = size; > } > > +#define read_for_each_sibling_event(sibling, event) \ > + if ((event)->group_leader == (event)) \ > + list_for_each_entry((sibling), &(event)->sibling_list, sibling_list) > + > /* > * Check that adding an event to the group does not result in anybody > * overflowing the 64k event limit imposed by the output buffer. > @@ -1957,7 +1961,7 @@ static bool perf_event_validate_size(struct perf_event *event) > if (event == group_leader) > return true; > > - for_each_sibling_event(sibling, group_leader) { > + read_for_each_sibling_event(sibling, group_leader) { > if (__perf_event_read_size(sibling->attr.read_format, > group_leader->nr_siblings + 1) > 16*1024) > return false; > -- > 2.43.0 >