Messages in this thread | | | Date | Wed, 24 Sep 2008 10:58:48 +0200 | From | Ingo Molnar <> | Subject | Re: [Patch -tip 0/4] Creation of the initcall tracer |
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* Frédéric Weisbecker <fweisbec@gmail.com> wrote:
> Ingo Molnar a écrit : > > * Ingo Molnar <mingo@elte.hu> wrote: > > > >> i've integrated tip/tracing/fastboot into tip/master and have started > >> testing it. It passed the basic tests already so i've just pushed out > >> the new tip/master. Please double-check that i have not messed up the > >> rename or the integration somewhere. > > > > FYI, -tip testing found a boot hang with CONFIG_BOOT_TRACER=y, on a > > 32-bit T60 laptop. I've attached the config that provokes the hang. (you > > need initcall_debug on the boot commandline) > > > > The hang always happens after a specific initcall, shortly after tracing > > is enabled. It just hangs indefinitely there, the last line displayed > > was: > > > > [ 0.004017] initcall ehci_hcd_init+0x0/0x80 returned 0 after 228 msecs > > > > it should have printed this next: > > > > [ 0.808024] calling ohci_hcd_mod_init+0x0/0x80 @ 10 > > > > but that line is never printed. > > > > i've bisected the hang down to this specific commit: > > > > | 35df98dfe2b2503436a8cfda301657810df50a3a is first bad commit > > | commit 35df98dfe2b2503436a8cfda301657810df50a3a > > | Author: Frédéric Weisbecker <fweisbec@gmail.com> > > | Date: Tue Sep 23 11:38:18 2008 +0100 > > | > > | tracing/ftrace: launch boot tracing after pre-smp initcalls > > > > An idea: maybe the boot tracer is interacting with the ftrace self-tests > > somehow? CONFIG_FTRACE_SELFTEST=y is enabled. > > > > another thing i noticed is that the sysprof tracer was initialized and > > self-tested shortly before the hang occured. Might be unrelated. > > > > the bisection log is: > > > > # bad: [6522eab5] Merge branch 'x86/uv' > > # good: [699b81f5] Merge branch 'x86/iommu' > > # bad: [8007aae9] timers: fix build error in !oneshot case > > # good: [7f29b23d] Merge branch 'core/rcu' > > # bad: [a54f17e3] manual merge of tracing/fastboot > > # good: [bcbbe946] tracing/ftrace: make tracing suitable to run the b > > # good: [d7095e5a] Merge branch 'fastboot' > > # bad: [35df98df] tracing/ftrace: launch boot tracing after pre-smp > > # good: [42aaa6be] tracing/ftrace: give an entry on the config for bo > > > > Ingo > > > Ingo Molnar a écrit : > > * Ingo Molnar <mingo@elte.hu> wrote: > > > >> i've integrated tip/tracing/fastboot into tip/master and have started > >> testing it. It passed the basic tests already so i've just pushed out > >> the new tip/master. Please double-check that i have not messed up the > >> rename or the integration somewhere. > > > > FYI, -tip testing found a boot hang with CONFIG_BOOT_TRACER=y, on a > > 32-bit T60 laptop. I've attached the config that provokes the hang. (you > > need initcall_debug on the boot commandline) > > > > The hang always happens after a specific initcall, shortly after tracing > > is enabled. It just hangs indefinitely there, the last line displayed > > was: > > > > [ 0.004017] initcall ehci_hcd_init+0x0/0x80 returned 0 after 228 msecs > > > > it should have printed this next: > > > > [ 0.808024] calling ohci_hcd_mod_init+0x0/0x80 @ 10 > > > > but that line is never printed. > > > > i've bisected the hang down to this specific commit: > > > > | 35df98dfe2b2503436a8cfda301657810df50a3a is first bad commit > > | commit 35df98dfe2b2503436a8cfda301657810df50a3a > > | Author: Frédéric Weisbecker <fweisbec@gmail.com> > > | Date: Tue Sep 23 11:38:18 2008 +0100 > > | > > | tracing/ftrace: launch boot tracing after pre-smp initcalls > > > > An idea: maybe the boot tracer is interacting with the ftrace self-tests > > somehow? CONFIG_FTRACE_SELFTEST=y is enabled. > > > > another thing i noticed is that the sysprof tracer was initialized and > > self-tested shortly before the hang occured. Might be unrelated. > > > > the bisection log is: > > > > # bad: [6522eab5] Merge branch 'x86/uv' > > # good: [699b81f5] Merge branch 'x86/iommu' > > # bad: [8007aae9] timers: fix build error in !oneshot case > > # good: [7f29b23d] Merge branch 'core/rcu' > > # bad: [a54f17e3] manual merge of tracing/fastboot > > # good: [bcbbe946] tracing/ftrace: make tracing suitable to run the b > > # good: [d7095e5a] Merge branch 'fastboot' > > # bad: [35df98df] tracing/ftrace: launch boot tracing after pre-smp > > # good: [42aaa6be] tracing/ftrace: give an entry on the config for bo > > > > Ingo > > > > Hehe! I was preparing a patch because I saw last night that the self-tests were reseting and touching the ring-buffer during the initcall tracing. > And now I can see the results of this problem.... > > Following is a patch that should fix it.
applied to tip/tracing/fastboot, thanks Frédéric!
Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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