Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Ingo Molnar:
 "Mostly tooling and PMU driver fixes, but also a number of late updates
  such as the reworking of the call-chain size limiting logic to make
  call-graph recording more robust, plus tooling side changes for the
  new 'backwards ring-buffer' extension to the perf ring-buffer"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
  perf record: Read from backward ring buffer
  perf record: Rename variable to make code clear
  perf record: Prevent reading invalid data in record__mmap_read
  perf evlist: Add API to pause/resume
  perf trace: Use the ptr->name beautifier as default for "filename" args
  perf trace: Use the fd->name beautifier as default for "fd" args
  perf report: Add srcline_from/to branch sort keys
  perf evsel: Record fd into perf_mmap
  perf evsel: Add overwrite attribute and check write_backward
  perf tools: Set buildid dir under symfs when --symfs is provided
  perf trace: Only auto set call-graph to "dwarf" when syscalls are being traced
  perf annotate: Sort list of recognised instructions
  perf annotate: Fix identification of ARM blt and bls instructions
  perf tools: Fix usage of max_stack sysctl
  perf callchain: Stop validating callchains by the max_stack sysctl
  perf trace: Fix exit_group() formatting
  perf top: Use machine->kptr_restrict_warned
  perf trace: Warn when trying to resolve kernel addresses with kptr_restrict=1
  perf machine: Do not bail out if not managing to read ref reloc symbol
  perf/x86/intel/p4: Trival indentation fix, remove space
  ...

1 files changed, 15 insertions, 20 deletions

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index f9644f79686c..b1772180c820 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -43,6 +43,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 
         machine->symbol_filter = NULL;
         machine->id_hdr_size = 0;
+        machine->kptr_restrict_warned = false;
         machine->comm_exec = false;
         machine->kernel_start = 0;
 
@@ -709,7 +710,7 @@ static struct dso *machine__get_kernel(struct machine *machine)
         if (machine__is_host(machine)) {
                 vmlinux_name = symbol_conf.vmlinux_name;
                 if (!vmlinux_name)
-                        vmlinux_name = "[kernel.kallsyms]";
+                        vmlinux_name = DSO__NAME_KALLSYMS;
 
                 kernel = machine__findnew_kernel(machine, vmlinux_name,
                                                  "[kernel]", DSO_TYPE_KERNEL);
@@ -1135,10 +1136,10 @@ int machine__create_kernel_maps(struct machine *machine)
 {
         struct dso *kernel = machine__get_kernel(machine);
         const char *name;
-        u64 addr = machine__get_running_kernel_start(machine, &name);
+        u64 addr;
         int ret;
 
-        if (!addr || kernel == NULL)
+        if (kernel == NULL)
                 return -1;
 
         ret = __machine__create_kernel_maps(machine, kernel);
@@ -1160,8 +1161,9 @@ int machine__create_kernel_maps(struct machine *machine)
          */
         map_groups__fixup_end(&machine->kmaps);
 
-        if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name,
-                                             addr)) {
+        addr = machine__get_running_kernel_start(machine, &name);
+        if (!addr) {
+        } else if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
                 machine__destroy_kernel_maps(machine);
                 return -1;
         }
@@ -1769,11 +1771,6 @@ static int resolve_lbr_callchain_sample(struct thread *thread,
                  */
                 int mix_chain_nr = i + 1 + lbr_nr + 1;
 
-                if (mix_chain_nr > (int)sysctl_perf_event_max_stack + PERF_MAX_BRANCH_DEPTH) {
-                        pr_warning("corrupted callchain. skipping...\n");
-                        return 0;
-                }
-
                 for (j = 0; j < mix_chain_nr; j++) {
                         if (callchain_param.order == ORDER_CALLEE) {
                                 if (j < i + 1)
@@ -1811,9 +1808,9 @@ static int thread__resolve_callchain_sample(struct thread *thread,
 {
         struct branch_stack *branch = sample->branch_stack;
         struct ip_callchain *chain = sample->callchain;
-        int chain_nr = min(max_stack, (int)chain->nr);
+        int chain_nr = chain->nr;
         u8 cpumode = PERF_RECORD_MISC_USER;
-        int i, j, err;
+        int i, j, err, nr_entries;
         int skip_idx = -1;
         int first_call = 0;
 
@@ -1828,8 +1825,7 @@ static int thread__resolve_callchain_sample(struct thread *thread,
          * Based on DWARF debug information, some architectures skip
          * a callchain entry saved by the kernel.
          */
-        if (chain->nr < sysctl_perf_event_max_stack)
-                skip_idx = arch_skip_callchain_idx(thread, chain);
+        skip_idx = arch_skip_callchain_idx(thread, chain);
 
         /*
          * Add branches to call stack for easier browsing. This gives
@@ -1889,12 +1885,8 @@ static int thread__resolve_callchain_sample(struct thread *thread,
         }
 
 check_calls:
-        if (chain->nr > sysctl_perf_event_max_stack && (int)chain->nr > max_stack) {
-                pr_warning("corrupted callchain. skipping...\n");
-                return 0;
-        }
-
-        for (i = first_call; i < chain_nr; i++) {
+        for (i = first_call, nr_entries = 0;
+             i < chain_nr && nr_entries < max_stack; i++) {
                 u64 ip;
 
                 if (callchain_param.order == ORDER_CALLEE)
@@ -1908,6 +1900,9 @@ check_calls:
 #endif
                 ip = chain->ips[j];
 
+                if (ip < PERF_CONTEXT_MAX)
+                       ++nr_entries;
+
                 err = add_callchain_ip(thread, cursor, parent, root_al, &cpumode, ip);
 
                 if (err)