From: Gautham R Shenoy <ego@linux.vnet.ibm.com> To: "Oliver O'Halloran" <oohall@gmail.com> Cc: linuxppc-dev@lists.ozlabs.org, svaidy@linux.vnet.ibm.com, Viresh Kumar <viresh.kumar@linaro.org>, linux-pm@vger.kernel.org Subject: Re: [PATCH 1/2] cpufreq/powernv: Fix use-after-free Date: Tue, 25 Feb 2020 12:12:35 +0530 [thread overview] Message-ID: <20200225064235.GI12846@in.ibm.com> (raw) In-Reply-To: <20200206062622.28235-1-oohall@gmail.com> On Thu, Feb 06, 2020 at 05:26:21PM +1100, Oliver O'Halloran wrote: > The cpufreq driver has a use-after-free that we can hit if: > > a) There's an OCC message pending when the notifier is registered, and > b) The cpufreq driver fails to register with the core. > > When a) occurs the notifier schedules a workqueue item to handle the > message. The backing work_struct is located on chips[].throttle and when b) > happens we clean up by freeing the array. Once we get to the (now free) > queued item and the kernel crashes. > > Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> > Fixes: c5e29ea ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}") > Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Thanks for this fix Oliver. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > --- > drivers/cpufreq/powernv-cpufreq.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c > index 56f4bc0..1806b1d 100644 > --- a/drivers/cpufreq/powernv-cpufreq.c > +++ b/drivers/cpufreq/powernv-cpufreq.c > @@ -1080,6 +1080,12 @@ static int init_chip_info(void) > > static inline void clean_chip_info(void) > { > + int i; > + > + /* flush any pending work items */ > + if (chips) > + for (i = 0; i < nr_chips; i++) > + cancel_work_sync(&chips[i].throttle); > kfree(chips); > } > > -- > 2.9.5 >
WARNING: multiple messages have this Message-ID (diff)
From: Gautham R Shenoy <ego@linux.vnet.ibm.com> To: "Oliver O'Halloran" <oohall@gmail.com> Cc: Viresh Kumar <viresh.kumar@linaro.org>, svaidy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-pm@vger.kernel.org Subject: Re: [PATCH 1/2] cpufreq/powernv: Fix use-after-free Date: Tue, 25 Feb 2020 12:12:35 +0530 [thread overview] Message-ID: <20200225064235.GI12846@in.ibm.com> (raw) In-Reply-To: <20200206062622.28235-1-oohall@gmail.com> On Thu, Feb 06, 2020 at 05:26:21PM +1100, Oliver O'Halloran wrote: > The cpufreq driver has a use-after-free that we can hit if: > > a) There's an OCC message pending when the notifier is registered, and > b) The cpufreq driver fails to register with the core. > > When a) occurs the notifier schedules a workqueue item to handle the > message. The backing work_struct is located on chips[].throttle and when b) > happens we clean up by freeing the array. Once we get to the (now free) > queued item and the kernel crashes. > > Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> > Fixes: c5e29ea ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}") > Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Thanks for this fix Oliver. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > --- > drivers/cpufreq/powernv-cpufreq.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c > index 56f4bc0..1806b1d 100644 > --- a/drivers/cpufreq/powernv-cpufreq.c > +++ b/drivers/cpufreq/powernv-cpufreq.c > @@ -1080,6 +1080,12 @@ static int init_chip_info(void) > > static inline void clean_chip_info(void) > { > + int i; > + > + /* flush any pending work items */ > + if (chips) > + for (i = 0; i < nr_chips; i++) > + cancel_work_sync(&chips[i].throttle); > kfree(chips); > } > > -- > 2.9.5 >
next prev parent reply other threads:[~2020-02-25 6:42 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-06 6:26 [PATCH 1/2] cpufreq/powernv: Fix use-after-free Oliver O'Halloran 2020-02-06 6:26 ` [PATCH 2/2] cpufreq/powernv: Fix unsafe notifiers Oliver O'Halloran 2020-02-25 6:45 ` Gautham R Shenoy 2020-02-25 6:45 ` Gautham R Shenoy 2020-02-25 6:42 ` Gautham R Shenoy [this message] 2020-02-25 6:42 ` [PATCH 1/2] cpufreq/powernv: Fix use-after-free Gautham R Shenoy 2020-02-25 7:03 ` Andrew Donnellan 2020-02-27 1:31 ` Michael Ellerman 2020-03-17 13:14 ` Michael Ellerman
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20200225064235.GI12846@in.ibm.com \ --to=ego@linux.vnet.ibm.com \ --cc=linux-pm@vger.kernel.org \ --cc=linuxppc-dev@lists.ozlabs.org \ --cc=oohall@gmail.com \ --cc=svaidy@linux.vnet.ibm.com \ --cc=viresh.kumar@linaro.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
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.