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authorOliver O'Halloran <oohall@gmail.com>2020-02-06 09:26:21 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2020-03-13 13:13:11 +0300
commitd0a72efac89d1c35ac55197895201b7b94c5e6ef (patch)
tree7ccd069c42df06af64cb6dd79d772ed3fd1f7fcf /drivers/cpufreq
parentffd3eaf178b0f616a071e510e289d937330b0b35 (diff)
downloadlinux-d0a72efac89d1c35ac55197895201b7b94c5e6ef.tar.xz
cpufreq: powernv: Fix use-after-free
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
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/powernv-cpufreq.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 56f4bc0d209e..1806b1da4366 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -1080,6 +1080,12 @@ 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);
}