From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guilherme G. Piccoli Date: Wed, 18 May 2022 10:16:20 -0300 Subject: [PATCH 19/30] panic: Add the panic hypervisor notifier list In-Reply-To: References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-20-gpiccoli@igalia.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org On 18/05/2022 04:58, Petr Mladek wrote: > [...] >> I does similar things like kmsg_dump() so it should be called in >> the same location (after info notifier list and before kdump). >> >> A solution might be to put it at these notifiers at the very >> end of the "info" list or make extra "dump" notifier list. > > I just want to point out that the above idea has problems. > Notifiers storing kernel log need to be treated as kmsg_dump(). > In particular, we would need to know if there are any. > We do not need to call "info" notifier list before kdump > when there is no kernel log dumper registered. > Notifiers respect the priority concept, which is just a number that orders the list addition (and the list is called in order). I've used the last position to panic_print() [in patch 25] - one idea here is to "reserve" the last position (represented by INT_MIN) for notifiers that act like kmsg_dump(). I couldn't find any IIRC, but that doesn't prevent us to save this position and comment about that. Makes sense to you ? Cheers!