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Re: [Qemu-devel] [PATCH] migration: fix crash in when incoming client ch
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH] migration: fix crash in when incoming client channel setup fails |
Date: |
Tue, 19 Jun 2018 16:45:05 +0100 |
User-agent: |
Mutt/1.10.0 (2018-05-17) |
* Daniel P. Berrangé (address@hidden) wrote:
> The way we determine if we can start the incoming migration was
> changed to use migration_has_all_channels() in:
>
> commit 428d89084c709e568f9cd301c2f6416a54c53d6d
> Author: Juan Quintela <address@hidden>
> Date: Mon Jul 24 13:06:25 2017 +0200
>
> migration: Create migration_has_all_channels
>
> This method in turn calls multifd_recv_all_channels_created()
> which is hardcoded to always return 'true' when multifd is
> not in use.
>
> This means that if channel initialization fails with normal
> migration, it'll never notice and attempt to start the
> incoming migration regardless.
I'm not sure if that was actually the cause, because older versions
had no check at all in socket_accept_incoming_migration.
> This can be seen, for example, if a client connects to a server
> requiring TLS, but has an invalid x509 certificate:
>
> qemu-system-x86_64: The certificate hasn't got a known issuer
> qemu-system-x86_64: migration/migration.c:386: process_incoming_migration_co:
> Assertion `mis->from_src_file' failed.
>
> #0 0x00007fffebd24f2b in raise () at /lib64/libc.so.6
> #1 0x00007fffebd0f561 in abort () at /lib64/libc.so.6
> #2 0x00007fffebd0f431 in _nl_load_domain.cold.0 () at /lib64/libc.so.6
> #3 0x00007fffebd1d692 in () at /lib64/libc.so.6
> #4 0x0000555555ad027e in process_incoming_migration_co (opaque=<optimized
> out>) at migration/migration.c:386
> #5 0x0000555555c45e8b in coroutine_trampoline (i0=<optimized out>,
> i1=<optimized out>) at util/coroutine-ucontext.c:116
> #6 0x00007fffebd3a6a0 in __start_context () at /lib64/libc.so.6
> #7 0x0000000000000000 in ()
>
> To handle the non-multifd case, we check whether mis->from_src_file
> is non-NULL.
So, what happens with this fix, does the destination exit cleanly, or
stay to accept another connection or what?
Dave
> Signed-off-by: Daniel P. Berrangé <address@hidden>
> ---
> migration/migration.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index e1eaa97df4..38ad818b23 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -518,11 +518,12 @@ void migration_ioc_process_incoming(QIOChannel *ioc)
> */
> bool migration_has_all_channels(void)
> {
> + MigrationIncomingState *mis = migration_incoming_get_current();
> bool all_channels;
>
> all_channels = multifd_recv_all_channels_created();
>
> - return all_channels;
> + return all_channels && mis->from_src_file != NULL;
> }
>
> /*
> --
> 2.17.0
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK