projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 931f3697 GKH |
1 | From foo@baz Tue Oct 28 11:19:22 CST 2014 |
| 2 | From: "David S. Miller" <davem@davemloft.net> | |
| 3 | Date: Mon, 11 Aug 2014 15:38:46 -0700 | |
| 4 | Subject: sparc64: Fix pcr_ops initialization and usage bugs. | |
| 5 | ||
| 6 | From: "David S. Miller" <davem@davemloft.net> | |
| 7 | ||
| 8 | [ Upstream commit 8bccf5b313180faefce38e0d1140f76e0f327d28 ] | |
| 9 | ||
| 10 | Christopher reports that perf_event_print_debug() can crash in uniprocessor | |
| 11 | builds. The crash is due to pcr_ops being NULL. | |
| 12 | ||
| 13 | This happens because pcr_arch_init() is only invoked by smp_cpus_done() which | |
| 14 | only executes in SMP builds. | |
| 15 | ||
| 16 | init_hw_perf_events() is closely intertwined with pcr_ops being setup properly, | |
| 17 | therefore: | |
| 18 | ||
| 19 | 1) Call pcr_arch_init() early on from init_hw_perf_events(), instead of | |
| 20 | from smp_cpus_done(). | |
| 21 | ||
| 22 | 2) Do not hook up a PMU type if pcr_ops is NULL after pcr_arch_init(). | |
| 23 | ||
| 24 | 3) Move init_hw_perf_events to a later initcall so that it we will be | |
| 25 | sure to invoke pcr_arch_init() after all cpus are brought up. | |
| 26 | ||
| 27 | Finally, guard the one naked sequence of pcr_ops dereferences in | |
| 28 | __global_pmu_self() with an appropriate NULL check. | |
| 29 | ||
| 30 | Reported-by: Christopher Alexander Tobias Schulze <cat.schulze@alice-dsl.net> | |
| 31 | Signed-off-by: David S. Miller <davem@davemloft.net> | |
| 32 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 33 | --- | |
| 34 | arch/sparc/kernel/perf_event.c | 7 +++++-- | |
| 35 | arch/sparc/kernel/process_64.c | 3 +++ | |
| 36 | arch/sparc/kernel/smp_64.c | 1 - | |
| 37 | 3 files changed, 8 insertions(+), 3 deletions(-) | |
| 38 | ||
| 39 | --- a/arch/sparc/kernel/perf_event.c | |
| 40 | +++ b/arch/sparc/kernel/perf_event.c | |
| 41 | @@ -1671,9 +1671,12 @@ static bool __init supported_pmu(void) | |
| 42 | ||
| 43 | static int __init init_hw_perf_events(void) | |
| 44 | { | |
| 45 | + int err; | |
| 46 | + | |
| 47 | pr_info("Performance events: "); | |
| 48 | ||
| 49 | - if (!supported_pmu()) { | |
| 50 | + err = pcr_arch_init(); | |
| 51 | + if (err || !supported_pmu()) { | |
| 52 | pr_cont("No support for PMU type '%s'\n", sparc_pmu_type); | |
| 53 | return 0; | |
| 54 | } | |
| 55 | @@ -1685,7 +1688,7 @@ static int __init init_hw_perf_events(vo | |
| 56 | ||
| 57 | return 0; | |
| 58 | } | |
| 59 | -early_initcall(init_hw_perf_events); | |
| 60 | +pure_initcall(init_hw_perf_events); | |
| 61 | ||
| 62 | void perf_callchain_kernel(struct perf_callchain_entry *entry, | |
| 63 | struct pt_regs *regs) | |
| 64 | --- a/arch/sparc/kernel/process_64.c | |
| 65 | +++ b/arch/sparc/kernel/process_64.c | |
| 66 | @@ -312,6 +312,9 @@ static void __global_pmu_self(int this_c | |
| 67 | struct global_pmu_snapshot *pp; | |
| 68 | int i, num; | |
| 69 | ||
| 70 | + if (!pcr_ops) | |
| 71 | + return; | |
| 72 | + | |
| 73 | pp = &global_cpu_snapshot[this_cpu].pmu; | |
| 74 | ||
| 75 | num = 1; | |
| 76 | --- a/arch/sparc/kernel/smp_64.c | |
| 77 | +++ b/arch/sparc/kernel/smp_64.c | |
| 78 | @@ -1383,7 +1383,6 @@ void __cpu_die(unsigned int cpu) | |
| 79 | ||
| 80 | void __init smp_cpus_done(unsigned int max_cpus) | |
| 81 | { | |
| 82 | - pcr_arch_init(); | |
| 83 | } | |
| 84 | ||
| 85 | void smp_send_reschedule(int cpu) |