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| author | Oliver O'Halloran <oohall@gmail.com> | 2020-02-06 09:26:21 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-17 11:48:52 +0300 |
| commit | 35e68aef65398eb3201d2e697b2cbff90ec40820 (patch) | |
| tree | 7216ec17848d000448981dbace6188aaf52e60cb /drivers/cpufreq | |
| parent | 2a87b491b7df0d935f6de9669414dc3fe7176b81 (diff) | |
| download | linux-35e68aef65398eb3201d2e697b2cbff90ec40820.tar.xz | |
cpufreq: powernv: Fix use-after-free
commit d0a72efac89d1c35ac55197895201b7b94c5e6ef upstream.
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.
Fixes: c5e29ea7ac14 ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200206062622.28235-1-oohall@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/powernv-cpufreq.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 5fff39dae625..687c92ef7644 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -1081,6 +1081,12 @@ free_and_return: 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); } |