| Message ID | 1512667407-30067-1-git-send-email-anju@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 110df8bd3e418b3476cae80babe8add48a8ea523 |
| Headers | show |
| Series | powerpc/perf: Fix kfree memory allocated for nest pmus | expand |
On Thursday 07 December 2017 10:53 PM, Anju T Sudhakar wrote: > imc_common_cpuhp_mem_free() is the common function for all IMC (In-memory > Collection counters) domains to unregister cpuhotplug callback and free memory. > Since kfree of memory allocated for nest-imc (per_nest_pmu_arr) is in the common > code, all domains (core/nest/thread) can do the kfree in the failure case. > > This could potentially create a call trace as shown below, where core(/thread/nest) > imc pmu initialization fails and in the failure path imc_common_cpuhp_mem_free() > free the memory(per_nest_pmu_arr), which is allocated by successfully registered > nest units. > > > The call trace is generated in a scenario where core-imc initialization is > made to fail and a cpuhotplug is performed in a p9 system. > During cpuhotplug ppc_nest_imc_cpu_offline() tries to access per_nest_pmu_arr, > which is already freed by core-imc. > > [ 136.563618] NIP [c000000000cb6a94] mutex_lock+0x34/0x90 > [ 136.563653] LR [c000000000cb6a88] mutex_lock+0x28/0x90 > [ 136.563687] Call Trace: > [ 136.563707] [c0000016b7a93b90] [c000000000cb6a88] mutex_lock+0x28/0x90 (unreliable) > [ 136.563762] [c0000016b7a93bc0] [c0000000002bc720] perf_pmu_migrate_context+0x90/0x3a0 > [ 136.563814] [c0000016b7a93c60] [c0000000000f7a40] ppc_nest_imc_cpu_offline+0x190/0x1f0 > [ 136.563867] [c0000016b7a93cb0] [c000000000108140] cpuhp_invoke_callback+0x160/0x820 > [ 136.563918] [c0000016b7a93d30] [c00000000010939c] cpuhp_thread_fun+0x1bc/0x270 > [ 136.563970] [c0000016b7a93d60] [c00000000013d2b0] smpboot_thread_fn+0x250/0x290 > [ 136.564022] [c0000016b7a93dc0] [c000000000136f18] kthread+0x1a8/0x1b0 > [ 136.564067] [c0000016b7a93e30] [c00000000000b4e8] ret_from_kernel_thread+0x5c/0x74 > > To address this scenario do the kfree(per_nest_pmu_arr) only in case of > nest-imc initialization failure, and when there is no other nest units registered. My bad. Broke it when fixing the IMC_MAX_PMU. Sorry about it. Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> > > Fixes: 73ce9aec65b1 ("powerpc/perf: Fix IMC_MAX_PMU macro") > Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> > --- > arch/powerpc/perf/imc-pmu.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c > index 0ead3cd..4eb9e2b 100644 > --- a/arch/powerpc/perf/imc-pmu.c > +++ b/arch/powerpc/perf/imc-pmu.c > @@ -1171,6 +1171,7 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr) > if (nest_pmus == 1) { > cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE); > kfree(nest_imc_refc); > + kfree(per_nest_pmu_arr); > } > > if (nest_pmus > 0) > @@ -1195,7 +1196,6 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr) > kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs); > kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]); > kfree(pmu_ptr); > - kfree(per_nest_pmu_arr); > return; > } > > @@ -1309,6 +1309,8 @@ int init_imc_pmu(struct device_node *parent, struct imc_pmu *pmu_ptr, int pmu_id > ret = nest_pmu_cpumask_init(); > if (ret) { > mutex_unlock(&nest_init_lock); > + kfree(nest_imc_refc); > + kfree(per_nest_pmu_arr); > goto err_free; > } > }
On Thu, 2017-12-07 at 17:23:27 UTC, Anju T Sudhakar wrote: > imc_common_cpuhp_mem_free() is the common function for all IMC (In-memory > Collection counters) domains to unregister cpuhotplug callback and free memory. > Since kfree of memory allocated for nest-imc (per_nest_pmu_arr) is in the common > code, all domains (core/nest/thread) can do the kfree in the failure case. > > This could potentially create a call trace as shown below, where core(/thread/nest) > imc pmu initialization fails and in the failure path imc_common_cpuhp_mem_free() > free the memory(per_nest_pmu_arr), which is allocated by successfully registered > nest units. > > > The call trace is generated in a scenario where core-imc initialization is > made to fail and a cpuhotplug is performed in a p9 system. > During cpuhotplug ppc_nest_imc_cpu_offline() tries to access per_nest_pmu_arr, > which is already freed by core-imc. > > [ 136.563618] NIP [c000000000cb6a94] mutex_lock+0x34/0x90 > [ 136.563653] LR [c000000000cb6a88] mutex_lock+0x28/0x90 > [ 136.563687] Call Trace: > [ 136.563707] [c0000016b7a93b90] [c000000000cb6a88] mutex_lock+0x28/0x90 (unreliable) > [ 136.563762] [c0000016b7a93bc0] [c0000000002bc720] perf_pmu_migrate_context+0x90/0x3a0 > [ 136.563814] [c0000016b7a93c60] [c0000000000f7a40] ppc_nest_imc_cpu_offline+0x190/0x1f0 > [ 136.563867] [c0000016b7a93cb0] [c000000000108140] cpuhp_invoke_callback+0x160/0x820 > [ 136.563918] [c0000016b7a93d30] [c00000000010939c] cpuhp_thread_fun+0x1bc/0x270 > [ 136.563970] [c0000016b7a93d60] [c00000000013d2b0] smpboot_thread_fn+0x250/0x290 > [ 136.564022] [c0000016b7a93dc0] [c000000000136f18] kthread+0x1a8/0x1b0 > [ 136.564067] [c0000016b7a93e30] [c00000000000b4e8] ret_from_kernel_thread+0x5c/0x74 > > To address this scenario do the kfree(per_nest_pmu_arr) only in case of > nest-imc initialization failure, and when there is no other nest units registered. > > > Fixes: 73ce9aec65b1 ("powerpc/perf: Fix IMC_MAX_PMU macro") > Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> > Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/110df8bd3e418b3476cae80babe8ad cheers
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c index 0ead3cd..4eb9e2b 100644 --- a/arch/powerpc/perf/imc-pmu.c +++ b/arch/powerpc/perf/imc-pmu.c @@ -1171,6 +1171,7 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr) if (nest_pmus == 1) { cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE); kfree(nest_imc_refc); + kfree(per_nest_pmu_arr); } if (nest_pmus > 0) @@ -1195,7 +1196,6 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr) kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs); kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]); kfree(pmu_ptr); - kfree(per_nest_pmu_arr); return; } @@ -1309,6 +1309,8 @@ int init_imc_pmu(struct device_node *parent, struct imc_pmu *pmu_ptr, int pmu_id ret = nest_pmu_cpumask_init(); if (ret) { mutex_unlock(&nest_init_lock); + kfree(nest_imc_refc); + kfree(per_nest_pmu_arr); goto err_free; } }
imc_common_cpuhp_mem_free() is the common function for all IMC (In-memory Collection counters) domains to unregister cpuhotplug callback and free memory. Since kfree of memory allocated for nest-imc (per_nest_pmu_arr) is in the common code, all domains (core/nest/thread) can do the kfree in the failure case. This could potentially create a call trace as shown below, where core(/thread/nest) imc pmu initialization fails and in the failure path imc_common_cpuhp_mem_free() free the memory(per_nest_pmu_arr), which is allocated by successfully registered nest units. The call trace is generated in a scenario where core-imc initialization is made to fail and a cpuhotplug is performed in a p9 system. During cpuhotplug ppc_nest_imc_cpu_offline() tries to access per_nest_pmu_arr, which is already freed by core-imc. [ 136.563618] NIP [c000000000cb6a94] mutex_lock+0x34/0x90 [ 136.563653] LR [c000000000cb6a88] mutex_lock+0x28/0x90 [ 136.563687] Call Trace: [ 136.563707] [c0000016b7a93b90] [c000000000cb6a88] mutex_lock+0x28/0x90 (unreliable) [ 136.563762] [c0000016b7a93bc0] [c0000000002bc720] perf_pmu_migrate_context+0x90/0x3a0 [ 136.563814] [c0000016b7a93c60] [c0000000000f7a40] ppc_nest_imc_cpu_offline+0x190/0x1f0 [ 136.563867] [c0000016b7a93cb0] [c000000000108140] cpuhp_invoke_callback+0x160/0x820 [ 136.563918] [c0000016b7a93d30] [c00000000010939c] cpuhp_thread_fun+0x1bc/0x270 [ 136.563970] [c0000016b7a93d60] [c00000000013d2b0] smpboot_thread_fn+0x250/0x290 [ 136.564022] [c0000016b7a93dc0] [c000000000136f18] kthread+0x1a8/0x1b0 [ 136.564067] [c0000016b7a93e30] [c00000000000b4e8] ret_from_kernel_thread+0x5c/0x74 To address this scenario do the kfree(per_nest_pmu_arr) only in case of nest-imc initialization failure, and when there is no other nest units registered. Fixes: 73ce9aec65b1 ("powerpc/perf: Fix IMC_MAX_PMU macro") Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> --- arch/powerpc/perf/imc-pmu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)