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authorLinus Torvalds <torvalds@linux-foundation.org>2020-05-14 11:46:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-14 11:46:52 -0700
commitf44d5c489051c2127189abb25d3d1625d9564c2d (patch)
tree6a9f4f2d47cbd7ec095d3926f9ad666adb123021 /arch
parentf492de9dcf04fde2b3671b9e188180fc684aa4e2 (diff)
parentda4d401a6b8fda7414033f81982f64ade02c0e27 (diff)
Merge tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull more tracing fixes from Steven Rostedt: "Various tracing fixes: - Fix a crash when having function tracing and function stack tracing on the command line. The ftrace trampolines are created as executable and read only. But the stack tracer tries to modify them with text_poke() which expects all kernel text to still be writable at boot. Keep the trampolines writable at boot, and convert them to read-only with the rest of the kernel. - A selftest was triggering in the ring buffer iterator code, that is no longer valid with the update of keeping the ring buffer writable while a iterator is reading. Just bail after three failed attempts to get an event and remove the warning and disabling of the ring buffer. - While modifying the ring buffer code, decided to remove all the unnecessary BUG() calls" * tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ring-buffer: Remove all BUG() calls ring-buffer: Don't deactivate the ring buffer on failed iterator reads x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/ftrace.h6
-rw-r--r--arch/x86/kernel/ftrace.c29
-rw-r--r--arch/x86/mm/init_64.c3
3 files changed, 37 insertions, 1 deletions
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 70b96cae5b42..84b9449be080 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -56,6 +56,12 @@ struct dyn_arch_ftrace {
#ifndef __ASSEMBLY__
+#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
+extern void set_ftrace_ops_ro(void);
+#else
+static inline void set_ftrace_ops_ro(void) { }
+#endif
+
#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
{
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 37a0aeaf89e7..b0e641793be4 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -407,7 +407,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
set_vm_flush_reset_perms(trampoline);
- set_memory_ro((unsigned long)trampoline, npages);
+ if (likely(system_state != SYSTEM_BOOTING))
+ set_memory_ro((unsigned long)trampoline, npages);
set_memory_x((unsigned long)trampoline, npages);
return (unsigned long)trampoline;
fail:
@@ -415,6 +416,32 @@ fail:
return 0;
}
+void set_ftrace_ops_ro(void)
+{
+ struct ftrace_ops *ops;
+ unsigned long start_offset;
+ unsigned long end_offset;
+ unsigned long npages;
+ unsigned long size;
+
+ do_for_each_ftrace_op(ops, ftrace_ops_list) {
+ if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
+ continue;
+
+ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
+ start_offset = (unsigned long)ftrace_regs_caller;
+ end_offset = (unsigned long)ftrace_regs_caller_end;
+ } else {
+ start_offset = (unsigned long)ftrace_caller;
+ end_offset = (unsigned long)ftrace_epilogue;
+ }
+ size = end_offset - start_offset;
+ size = size + RET_SIZE + sizeof(void *);
+ npages = DIV_ROUND_UP(size, PAGE_SIZE);
+ set_memory_ro((unsigned long)ops->trampoline, npages);
+ } while_for_each_ftrace_op(ops);
+}
+
static unsigned long calc_trampoline_call_offset(bool save_regs)
{
unsigned long start_offset;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 3b289c2f75cd..8b5f73f5e207 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -54,6 +54,7 @@
#include <asm/init.h>
#include <asm/uv/uv.h>
#include <asm/setup.h>
+#include <asm/ftrace.h>
#include "mm_internal.h"
@@ -1291,6 +1292,8 @@ void mark_rodata_ro(void)
all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT);
+ set_ftrace_ops_ro();
+
#ifdef CONFIG_CPA_DEBUG
printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, end);
set_memory_rw(start, (end-start) >> PAGE_SHIFT);