From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ananth Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <arapov@gmail.com>,
David Long <dave.long@linaro.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
"Frank Ch. Eigler" <fche@redhat.com>,
Ingo Molnar <mingo@kernel.org>, Jan Willeke <willeke@de.ibm.com>,
Jim Keniston <jkenisto@us.ibm.com>,
Mark Wielaard <mjw@redhat.com>,
Pratyush Anand <panand@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 11/11] uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more clever
Date: Fri, 10 Jul 2015 17:37:15 +0530 [thread overview]
Message-ID: <20150710120715.GK26095@linux.vnet.ibm.com> (raw)
In-Reply-To: <20150707012313.GA7557@redhat.com>
> If you ret-probe func_1() and func_2() prepare_uretprobe() hits the
> MAX_URETPROBE_DEPTH limit and "return" from func_2() is not reported.
>
> When we know that the new call is not chained, we can do the more
> strict check. In this case "sp" points to the new ret-addr, so every
> frame which uses the same "sp" must be dead. The only complication is
> that arch_uretprobe_is_alive() needs to know was it chained or not, so
> we add the new RP_CHECK_CHAIN_CALL enum and change prepare_uretprobe()
> to pass RP_CHECK_CALL only if !chained.
>
> Note: arch_uretprobe_is_alive() could also re-read *sp and check if
> this word is still trampoline_vaddr. This could obviously improve the
> logic, but I would like to avoid another copy_from_user() especially
> in the case when we can't avoid the false "alive == T" positives.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Looks good to me.
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
--
Thanks and Regards
Srikar Dronamraju
next prev parent reply other threads:[~2015-07-10 12:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-07 1:22 [PATCH v2 00/11] uprobes: longjmp fixes Oleg Nesterov
2015-07-07 1:22 ` [PATCH v2 01/11] uprobes: Introduce get_uprobe() Oleg Nesterov
2015-07-07 12:44 ` Anton Arapov
2015-07-07 1:22 ` [PATCH v2 02/11] uprobes: Introduce free_ret_instance() Oleg Nesterov
2015-07-07 12:46 ` Anton Arapov
2015-07-07 1:22 ` [PATCH v2 03/11] uprobes: Send SIGILL if handle_trampoline() fails Oleg Nesterov
2015-07-07 12:51 ` Anton Arapov
2015-07-07 1:22 ` [PATCH v2 04/11] uprobes: Change prepare_uretprobe() to use uprobe_warn() Oleg Nesterov
2015-07-07 12:52 ` Anton Arapov
2015-07-07 1:22 ` [PATCH v2 05/11] uprobes: Change handle_trampoline() to find the next chain beforehand Oleg Nesterov
2015-07-07 12:54 ` Anton Arapov
2015-07-07 1:22 ` [PATCH v2 06/11] uprobes: Export struct return_instance, introduce arch_uretprobe_is_alive() Oleg Nesterov
2015-07-07 12:58 ` Anton Arapov
2015-07-10 11:52 ` Srikar Dronamraju
2015-07-07 1:22 ` [PATCH v2 07/11] uprobes/x86: Reimplement arch_uretprobe_is_alive() Oleg Nesterov
2015-07-07 13:02 ` Anton Arapov
2015-07-10 11:53 ` Srikar Dronamraju
2015-07-07 1:23 ` [PATCH v2 08/11] uprobes: Change handle_trampoline() to flush the frames invalidated by longjmp() Oleg Nesterov
2015-07-07 13:05 ` Anton Arapov
2015-07-10 11:55 ` Srikar Dronamraju
2015-07-07 1:23 ` [PATCH v2 09/11] uprobes: Change prepare_uretprobe() to (try to) flush the dead frames Oleg Nesterov
2015-07-07 13:07 ` Anton Arapov
2015-07-10 11:57 ` Srikar Dronamraju
2015-07-07 1:23 ` [PATCH v2 10/11] uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive() Oleg Nesterov
2015-07-07 13:08 ` Anton Arapov
2015-07-10 12:06 ` Srikar Dronamraju
2015-07-07 1:23 ` [PATCH v2 11/11] uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more clever Oleg Nesterov
2015-07-07 13:11 ` Anton Arapov
2015-07-10 12:07 ` Srikar Dronamraju [this message]
2015-07-10 12:01 ` [PATCH v2 00/11] uprobes: longjmp fixes Pratyush Anand
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