Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On 14/11/14 02:16, Steven Rostedt wrote: > On Mon, 10 Nov 2014 09:41:32 + > Daniel Thompson wrote: > >> On 06/11/14 13:27, Steven Rostedt wrote: >>> On Thu, 6 Nov 2014 12:41:54 + >>> Daniel Thompson wrote: >>> This patchset makes it possible to use kdb's ftdump command without panicing, crashing or livelocking. The ftdump command cannot be used at all without these changes. IIRC this patches are still pending Jason's ack. >>> >>> I haven't heard from Jason in a long time. Is he still active? >> >> [sorry for the delay, I wanted to give Jason a chance to answer this] >> >> Very occasionally. >> >> I can't find anything on lkml in the last three months, and I have >> unreviewed kdb patches that stretch back well beyond that. >> >> That said he still helps people on kgdb-bugreport@ from time-to-time >> (and as recently as last week). I've also had a little bit of private >> contact although nothing very recent. >> >> On that basis I'd say you shouldn't feel guilty if you have to accept a >> change here without an ack. >> > > He had more than enough time to respond. OK, I'll take it. > > Looking at the first patch, I notice that there's no protection of the > static buffer_iter array. I also noticed that there's no protection of > the static iter itself (which was there before your patch). I take it > that this code is not re-entrant. No. k(g)db halts all other processors before entering the command dispatch loop and it forces a kernel panic if the debugger is reentered by the same CPU. Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On 14/11/14 02:16, Steven Rostedt wrote: On Mon, 10 Nov 2014 09:41:32 + Daniel Thompson daniel.thomp...@linaro.org wrote: On 06/11/14 13:27, Steven Rostedt wrote: On Thu, 6 Nov 2014 12:41:54 + Daniel Thompson daniel.thomp...@linaro.org wrote: This patchset makes it possible to use kdb's ftdump command without panicing, crashing or livelocking. The ftdump command cannot be used at all without these changes. IIRC this patches are still pending Jason's ack. I haven't heard from Jason in a long time. Is he still active? [sorry for the delay, I wanted to give Jason a chance to answer this] Very occasionally. I can't find anything on lkml in the last three months, and I have unreviewed kdb patches that stretch back well beyond that. That said he still helps people on kgdb-bugreport@ from time-to-time (and as recently as last week). I've also had a little bit of private contact although nothing very recent. On that basis I'd say you shouldn't feel guilty if you have to accept a change here without an ack. He had more than enough time to respond. OK, I'll take it. Looking at the first patch, I notice that there's no protection of the static buffer_iter array. I also noticed that there's no protection of the static iter itself (which was there before your patch). I take it that this code is not re-entrant. No. k(g)db halts all other processors before entering the command dispatch loop and it forces a kernel panic if the debugger is reentered by the same CPU. Daniel. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On Mon, 10 Nov 2014 09:41:32 + Daniel Thompson wrote: > On 06/11/14 13:27, Steven Rostedt wrote: > > On Thu, 6 Nov 2014 12:41:54 + > > Daniel Thompson wrote: > > > >> This patchset makes it possible to use kdb's ftdump command without > >> panicing, crashing or livelocking. The ftdump command cannot be used > >> at all without these changes. > >> > >> IIRC this patches are still pending Jason's ack. > > > > I haven't heard from Jason in a long time. Is he still active? > > [sorry for the delay, I wanted to give Jason a chance to answer this] > > Very occasionally. > > I can't find anything on lkml in the last three months, and I have > unreviewed kdb patches that stretch back well beyond that. > > That said he still helps people on kgdb-bugreport@ from time-to-time > (and as recently as last week). I've also had a little bit of private > contact although nothing very recent. > > On that basis I'd say you shouldn't feel guilty if you have to accept a > change here without an ack. > He had more than enough time to respond. OK, I'll take it. Looking at the first patch, I notice that there's no protection of the static buffer_iter array. I also noticed that there's no protection of the static iter itself (which was there before your patch). I take it that this code is not re-entrant. Thanks! -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On Mon, 10 Nov 2014 09:41:32 + Daniel Thompson daniel.thomp...@linaro.org wrote: On 06/11/14 13:27, Steven Rostedt wrote: On Thu, 6 Nov 2014 12:41:54 + Daniel Thompson daniel.thomp...@linaro.org wrote: This patchset makes it possible to use kdb's ftdump command without panicing, crashing or livelocking. The ftdump command cannot be used at all without these changes. IIRC this patches are still pending Jason's ack. I haven't heard from Jason in a long time. Is he still active? [sorry for the delay, I wanted to give Jason a chance to answer this] Very occasionally. I can't find anything on lkml in the last three months, and I have unreviewed kdb patches that stretch back well beyond that. That said he still helps people on kgdb-bugreport@ from time-to-time (and as recently as last week). I've also had a little bit of private contact although nothing very recent. On that basis I'd say you shouldn't feel guilty if you have to accept a change here without an ack. He had more than enough time to respond. OK, I'll take it. Looking at the first patch, I notice that there's no protection of the static buffer_iter array. I also noticed that there's no protection of the static iter itself (which was there before your patch). I take it that this code is not re-entrant. Thanks! -- Steve -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On 06/11/14 13:27, Steven Rostedt wrote: > On Thu, 6 Nov 2014 12:41:54 + > Daniel Thompson wrote: > >> This patchset makes it possible to use kdb's ftdump command without >> panicing, crashing or livelocking. The ftdump command cannot be used >> at all without these changes. >> >> IIRC this patches are still pending Jason's ack. > > I haven't heard from Jason in a long time. Is he still active? [sorry for the delay, I wanted to give Jason a chance to answer this] Very occasionally. I can't find anything on lkml in the last three months, and I have unreviewed kdb patches that stretch back well beyond that. That said he still helps people on kgdb-bugreport@ from time-to-time (and as recently as last week). I've also had a little bit of private contact although nothing very recent. On that basis I'd say you shouldn't feel guilty if you have to accept a change here without an ack. Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On 06/11/14 13:27, Steven Rostedt wrote: On Thu, 6 Nov 2014 12:41:54 + Daniel Thompson daniel.thomp...@linaro.org wrote: This patchset makes it possible to use kdb's ftdump command without panicing, crashing or livelocking. The ftdump command cannot be used at all without these changes. IIRC this patches are still pending Jason's ack. I haven't heard from Jason in a long time. Is he still active? [sorry for the delay, I wanted to give Jason a chance to answer this] Very occasionally. I can't find anything on lkml in the last three months, and I have unreviewed kdb patches that stretch back well beyond that. That said he still helps people on kgdb-bugreport@ from time-to-time (and as recently as last week). I've also had a little bit of private contact although nothing very recent. On that basis I'd say you shouldn't feel guilty if you have to accept a change here without an ack. Daniel. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On Thu, 6 Nov 2014 12:41:54 + Daniel Thompson wrote: > This patchset makes it possible to use kdb's ftdump command without > panicing, crashing or livelocking. The ftdump command cannot be used > at all without these changes. > > IIRC this patches are still pending Jason's ack. I haven't heard from Jason in a long time. Is he still active? -- Steve > > Changes since v1: > > * Fixed use-after-free problems in v1 by adding logic to NULL out > buffer_iter during free operations. > > * Introduced a second patch to fix a live lock when trying to display > an empty trace buffer. > > > Daniel Thompson (2): > trace: kdb: Fix kernel panic during ftdump > trace: kdb: Fix kernel livelock with empty buffers > > kernel/trace/trace_kdb.c | 21 + > 1 file changed, 13 insertions(+), 8 deletions(-) > > -- > 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH RESEND 3.18-rc3 v2 0/2] trace: kdb: Bug fixes for ftdump
On Thu, 6 Nov 2014 12:41:54 + Daniel Thompson daniel.thomp...@linaro.org wrote: This patchset makes it possible to use kdb's ftdump command without panicing, crashing or livelocking. The ftdump command cannot be used at all without these changes. IIRC this patches are still pending Jason's ack. I haven't heard from Jason in a long time. Is he still active? -- Steve Changes since v1: * Fixed use-after-free problems in v1 by adding logic to NULL out buffer_iter during free operations. * Introduced a second patch to fix a live lock when trying to display an empty trace buffer. Daniel Thompson (2): trace: kdb: Fix kernel panic during ftdump trace: kdb: Fix kernel livelock with empty buffers kernel/trace/trace_kdb.c | 21 + 1 file changed, 13 insertions(+), 8 deletions(-) -- 1.9.3 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
