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| author | Oliver O'Halloran <oohall@gmail.com> | 2020-02-06 17:26:21 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-24 07:58:59 +0200 |
| commit | 88a8e3c5a4c6bd353dc69b48f4a9d9331d19299d (patch) | |
| tree | 6303c973e92990f4e5354ef5e14eb43479c2c392 | |
| parent | f5fbbb67f27aa65d4c15a19760b42f292955c9e3 (diff) | |
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>
| -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 a1d7fa48229d..b4fc65512aad 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -955,6 +955,12 @@ 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); } |