* domain_crash_sync vs "plain crash" @ 2018-05-07 1:06 Charles Gonçalves 2018-05-07 7:09 ` Jan Beulich 0 siblings, 1 reply; 6+ messages in thread From: Charles Gonçalves @ 2018-05-07 1:06 UTC (permalink / raw) To: xen-devel [-- Attachment #1.1: Type: text/plain, Size: 481 bytes --] When I'm performing some hypercalls with some "unexpected" parameters (robustness test) sometimes the guest is explicitly "killed" by xen calling the domain_crash(), but sometimes the guest just crash without any explicit message on dmesg or logs. Are those "plain crashes" an expected behavior by design on Xen or are they some untreated parameter checking or something else? Can someone comment about it? Thanks! -- Atenciosamente, Charles F.'. Gonçalves [-- Attachment #1.2: Type: text/html, Size: 755 bytes --] [-- Attachment #2: Type: text/plain, Size: 157 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: domain_crash_sync vs "plain crash" 2018-05-07 1:06 domain_crash_sync vs "plain crash" Charles Gonçalves @ 2018-05-07 7:09 ` Jan Beulich 2018-05-07 8:13 ` Andrew Cooper 2018-05-11 22:43 ` Charles Gonçalves 0 siblings, 2 replies; 6+ messages in thread From: Jan Beulich @ 2018-05-07 7:09 UTC (permalink / raw) To: Charles Gonçalves; +Cc: xen-devel >>> On 07.05.18 at 03:06, <charles.fg@gmail.com> wrote: > When I'm performing some hypercalls with some "unexpected" parameters > (robustness test) sometimes the guest is explicitly "killed" by xen > calling the domain_crash(), but sometimes the guest just crash without any > explicit message on dmesg or logs. > > Are those "plain crashes" an expected behavior by design on Xen or are they > some untreated parameter checking or something else? A silent crash is never supposed to happen, but you always need to first consider whether the crashing component actually has a way to get something out to wherever you monitor its logs. That is, without (physical or virtual, depending on component) serial console you're often unlikely to actually observe any messages connected to the crash. If you can track down a _truly_ silent crash to its origin, submitting a patch to make it non-silent would be appreciated. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: domain_crash_sync vs "plain crash" 2018-05-07 7:09 ` Jan Beulich @ 2018-05-07 8:13 ` Andrew Cooper 2018-05-11 22:46 ` Charles Gonçalves 2018-05-11 22:43 ` Charles Gonçalves 1 sibling, 1 reply; 6+ messages in thread From: Andrew Cooper @ 2018-05-07 8:13 UTC (permalink / raw) To: Jan Beulich, Charles Gonçalves; +Cc: xen-devel On 07/05/2018 08:09, Jan Beulich wrote: >>>> On 07.05.18 at 03:06, <charles.fg@gmail.com> wrote: >> When I'm performing some hypercalls with some "unexpected" parameters >> (robustness test) sometimes the guest is explicitly "killed" by xen >> calling the domain_crash(), but sometimes the guest just crash without any >> explicit message on dmesg or logs. >> >> Are those "plain crashes" an expected behavior by design on Xen or are they >> some untreated parameter checking or something else? > A silent crash is never supposed to happen, but you always need to first > consider whether the crashing component actually has a way to get > something out to wherever you monitor its logs. That is, without (physical > or virtual, depending on component) serial console you're often unlikely to > actually observe any messages connected to the crash. > > If you can track down a _truly_ silent crash to its origin, submitting a patch > to make it non-silent would be appreciated. Alternatively, if you are fuzzing the hypercalls, which it sounds like you are, then you need to ensure that you blacklist operations such as SCHEDOP_shutdown and SCHEDOP_poll to avoid the fuzzer hitting legitimate hypercalls which shut down or block for indefinite periods of time. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: domain_crash_sync vs "plain crash" 2018-05-07 8:13 ` Andrew Cooper @ 2018-05-11 22:46 ` Charles Gonçalves 0 siblings, 0 replies; 6+ messages in thread From: Charles Gonçalves @ 2018-05-11 22:46 UTC (permalink / raw) To: Andrew Cooper; +Cc: Jan Beulich, xen-devel [-- Attachment #1.1: Type: text/plain, Size: 1573 bytes --] @Andrew, Despite SCHED_OP, that I've blacklisted, which one came to mind? On Mon, May 7, 2018 at 5:13 AM Andrew Cooper <andrew.cooper3@citrix.com> wrote: > On 07/05/2018 08:09, Jan Beulich wrote: > >>>> On 07.05.18 at 03:06, <charles.fg@gmail.com> wrote: > >> When I'm performing some hypercalls with some "unexpected" parameters > >> (robustness test) sometimes the guest is explicitly "killed" by xen > >> calling the domain_crash(), but sometimes the guest just crash without > any > >> explicit message on dmesg or logs. > >> > >> Are those "plain crashes" an expected behavior by design on Xen or are > they > >> some untreated parameter checking or something else? > > A silent crash is never supposed to happen, but you always need to first > > consider whether the crashing component actually has a way to get > > something out to wherever you monitor its logs. That is, without > (physical > > or virtual, depending on component) serial console you're often unlikely > to > > actually observe any messages connected to the crash. > > > > If you can track down a _truly_ silent crash to its origin, submitting a > patch > > to make it non-silent would be appreciated. > > Alternatively, if you are fuzzing the hypercalls, which it sounds like > you are, then you need to ensure that you blacklist operations such as > SCHEDOP_shutdown and SCHEDOP_poll to avoid the fuzzer hitting legitimate > hypercalls which shut down or block for indefinite periods of time. > > ~Andrew > -- Atenciosamente, Charles F.'. Gonçalves [-- Attachment #1.2: Type: text/html, Size: 2185 bytes --] [-- Attachment #2: Type: text/plain, Size: 157 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: domain_crash_sync vs "plain crash" 2018-05-07 7:09 ` Jan Beulich 2018-05-07 8:13 ` Andrew Cooper @ 2018-05-11 22:43 ` Charles Gonçalves 2018-05-16 8:08 ` Wei Liu 1 sibling, 1 reply; 6+ messages in thread From: Charles Gonçalves @ 2018-05-11 22:43 UTC (permalink / raw) To: Jan Beulich; +Cc: xen-devel [-- Attachment #1.1: Type: text/plain, Size: 411 bytes --] "That is, without (physical or virtual, depending on component) serial console you're often unlikely to actually observe any messages connected to the crash." I do not have any experience with serial console interaction on linux. Can you list some examples for both cases (virtual| physical), I'll glad to fully report any suspicious problem. Thanks! -- Atenciosamente, Charles F.'. Gonçalves [-- Attachment #1.2: Type: text/html, Size: 1095 bytes --] [-- Attachment #2: Type: text/plain, Size: 157 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: domain_crash_sync vs "plain crash" 2018-05-11 22:43 ` Charles Gonçalves @ 2018-05-16 8:08 ` Wei Liu 0 siblings, 0 replies; 6+ messages in thread From: Wei Liu @ 2018-05-16 8:08 UTC (permalink / raw) To: Charles Gonçalves; +Cc: Wei Liu, Jan Beulich, xen-devel On Fri, May 11, 2018 at 07:43:58PM -0300, Charles Gonçalves wrote: > "That is, without (physical > or virtual, depending on component) serial console you're often unlikely to > actually observe any messages connected to the crash." > > I do not have any experience with serial console interaction on linux. > Can you list some examples for both cases (virtual| physical), I'll glad to > fully report any suspicious problem. > > Thanks! > See https://wiki.xenproject.org/wiki/Xen_Serial_Console Wei. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-05-16 8:08 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-05-07 1:06 domain_crash_sync vs "plain crash" Charles Gonçalves 2018-05-07 7:09 ` Jan Beulich 2018-05-07 8:13 ` Andrew Cooper 2018-05-11 22:46 ` Charles Gonçalves 2018-05-11 22:43 ` Charles Gonçalves 2018-05-16 8:08 ` Wei Liu
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.