diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/Makefile | 51 | ||||
| -rw-r--r-- | kernel/trace/trace_remote.c | 22 |
2 files changed, 64 insertions, 9 deletions
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 3182e1bc1cf7..d662c1a64cd5 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -136,14 +136,53 @@ obj-$(CONFIG_TRACE_REMOTE_TEST) += remote_test.o # simple_ring_buffer is used by the pKVM hypervisor which does not have access # to all kernel symbols. Fail the build if forbidden symbols are found. # -UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __gcov __aeabi_unwind -UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer -UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST)) +# undefsyms_base generates a set of compiler and tooling-generated symbols that can +# safely be ignored for simple_ring_buffer. +# +filechk_undefsyms_base = \ + echo '$(pound)include <linux/atomic.h>'; \ + echo '$(pound)include <linux/string.h>'; \ + echo '$(pound)include <asm/page.h>'; \ + echo 'static char page[PAGE_SIZE] __aligned(PAGE_SIZE);'; \ + echo 'void undefsyms_base(void *p, int n);'; \ + echo 'void undefsyms_base(void *p, int n) {'; \ + echo ' char buffer[256] = { 0 };'; \ + echo ' u32 u = 0;'; \ + echo ' memset((char * volatile)page, 8, PAGE_SIZE);'; \ + echo ' memset((char * volatile)buffer, 8, sizeof(buffer));'; \ + echo ' memcpy((void * volatile)p, buffer, sizeof(buffer));'; \ + echo ' cmpxchg((u32 * volatile)&u, 0, 8);'; \ + echo ' WARN_ON(n == 0xdeadbeef);'; \ + echo '}' + +$(obj)/undefsyms_base.c: FORCE + $(call filechk,undefsyms_base) + +clean-files += undefsyms_base.c + +$(obj)/undefsyms_base.o: $(obj)/undefsyms_base.c + +targets += undefsyms_base.o + +# Ensure KASAN is enabled to avoid logic that may disable FORTIFY_SOURCE when +# KASAN is not enabled. undefsyms_base.o does not automatically get KASAN flags +# because it is not linked into vmlinux. +KASAN_SANITIZE_undefsyms_base.o := y + +UNDEFINED_ALLOWLIST = __asan __gcov __kasan __kcsan __hwasan __sancov __sanitizer __tsan __ubsan __x86_indirect_thunk \ + __msan simple_ring_buffer \ + $(shell $(NM) -u $(obj)/undefsyms_base.o 2>/dev/null | awk '{print $$2}') quiet_cmd_check_undefined = NM $< - cmd_check_undefined = test -z "`$(NM) -u $< | grep -v $(UNDEFINED_ALLOWLIST)`" - -$(obj)/%.o.checked: $(obj)/%.o FORCE + cmd_check_undefined = \ + undefsyms=$$($(NM) -u $< | grep -v $(addprefix -e , $(UNDEFINED_ALLOWLIST)) || true); \ + if [ -n "$$undefsyms" ]; then \ + echo "Unexpected symbols in $<:" >&2; \ + echo "$$undefsyms" >&2; \ + false; \ + fi + +$(obj)/%.o.checked: $(obj)/%.o $(obj)/undefsyms_base.o FORCE $(call if_changed,check_undefined) always-$(CONFIG_SIMPLE_RING_BUFFER) += simple_ring_buffer.o.checked diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index 0d78e5f5fe98..d6c3f94d67cd 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -282,6 +282,14 @@ static void trace_remote_put(struct trace_remote *remote) trace_remote_try_unload(remote); } +static bool trace_remote_has_cpu(struct trace_remote *remote, int cpu) +{ + if (cpu == RING_BUFFER_ALL_CPUS) + return true; + + return ring_buffer_poll_remote(remote->trace_buffer, cpu) == 0; +} + static void __poll_remote(struct work_struct *work) { struct delayed_work *dwork = to_delayed_work(work); @@ -324,6 +332,10 @@ static int __alloc_ring_buffer_iter(struct trace_remote_iterator *iter, int cpu) iter->rb_iters[cpu] = ring_buffer_read_start(iter->remote->trace_buffer, cpu, GFP_KERNEL); if (!iter->rb_iters[cpu]) { + /* This CPU isn't part of trace_buffer. Skip it */ + if (!trace_remote_has_cpu(iter->remote, cpu)) + continue; + __free_ring_buffer_iter(iter, RING_BUFFER_ALL_CPUS); return -ENOMEM; } @@ -347,10 +359,10 @@ static struct trace_remote_iterator if (ret) return ERR_PTR(ret); - /* Test the CPU */ - ret = ring_buffer_poll_remote(remote->trace_buffer, cpu); - if (ret) + if (!trace_remote_has_cpu(remote, cpu)) { + ret = -ENODEV; goto err; + } iter = kzalloc_obj(*iter); if (iter) { @@ -361,6 +373,7 @@ static struct trace_remote_iterator switch (type) { case TRI_CONSUMING: + ring_buffer_poll_remote(remote->trace_buffer, cpu); INIT_DELAYED_WORK(&iter->poll_work, __poll_remote); schedule_delayed_work(&iter->poll_work, msecs_to_jiffies(remote->poll_ms)); break; @@ -476,6 +489,9 @@ __peek_event(struct trace_remote_iterator *iter, int cpu, u64 *ts, unsigned long return ring_buffer_peek(iter->remote->trace_buffer, cpu, ts, lost_events); case TRI_NONCONSUMING: rb_iter = __get_rb_iter(iter, cpu); + if (!rb_iter) + return NULL; + rb_evt = ring_buffer_iter_peek(rb_iter, ts); if (!rb_evt) return NULL; |