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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-27 08:30:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-27 08:30:30 -0700
commit77d64656950b299f5e7c70f1e3a0bdc991b51497 (patch)
tree91e5a8c9d9e5e791301225e4e0b658b4fd5b3e81
parentc86daad2c25bfd4a33d48b7691afaa96d9c5ab46 (diff)
parent6ee98ffeea0bc9e072e419497d78697d8afcdd6d (diff)
downloadlinux-77d64656950b299f5e7c70f1e3a0bdc991b51497.tar.bz2
Merge tag 'trace-v4.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fixes from Steven Rostedt: "There's been a few memory issues found with ftrace. One was simply a memory leak where not all was being freed that should have been in releasing a file pointer on set_graph_function. Then Thomas found that the ftrace trampolines were marked for read/write as well as execute. To shrink the possible attack surface, he added calls to set them to ro. Which also uncovered some other issues with freeing module allocated memory that had its permissions changed. Kprobes had a similar issue which is fixed and a selftest was added to trigger that issue again" * tag 'trace-v4.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: x86/ftrace: Make sure that ftrace trampolines are not RWX x86/mm/ftrace: Do not bug in early boot on irqs_disabled in cpu_flush_range() selftests/ftrace: Add a testcase for many kprobe events kprobes/x86: Fix to set RWX bits correctly before releasing trampoline ftrace: Fix memory leak in ftrace_graph_release()
-rw-r--r--arch/x86/kernel/ftrace.c20
-rw-r--r--arch/x86/kernel/kprobes/core.c9
-rw-r--r--arch/x86/mm/pageattr.c2
-rw-r--r--kernel/kprobes.c2
-rw-r--r--kernel/trace/ftrace.c2
-rw-r--r--tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc21
6 files changed, 47 insertions, 9 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 0651e974dcb3..9bef1bbeba63 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -689,8 +689,12 @@ static inline void *alloc_tramp(unsigned long size)
{
return module_alloc(size);
}
-static inline void tramp_free(void *tramp)
+static inline void tramp_free(void *tramp, int size)
{
+ int npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+ set_memory_nx((unsigned long)tramp, npages);
+ set_memory_rw((unsigned long)tramp, npages);
module_memfree(tramp);
}
#else
@@ -699,7 +703,7 @@ static inline void *alloc_tramp(unsigned long size)
{
return NULL;
}
-static inline void tramp_free(void *tramp) { }
+static inline void tramp_free(void *tramp, int size) { }
#endif
/* Defined as markers to the end of the ftrace default trampolines */
@@ -771,7 +775,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* Copy ftrace_caller onto the trampoline memory */
ret = probe_kernel_read(trampoline, (void *)start_offset, size);
if (WARN_ON(ret < 0)) {
- tramp_free(trampoline);
+ tramp_free(trampoline, *tramp_size);
return 0;
}
@@ -797,7 +801,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* Are we pointing to the reference? */
if (WARN_ON(memcmp(op_ptr.op, op_ref, 3) != 0)) {
- tramp_free(trampoline);
+ tramp_free(trampoline, *tramp_size);
return 0;
}
@@ -839,7 +843,7 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
unsigned long offset;
unsigned long ip;
unsigned int size;
- int ret;
+ int ret, npages;
if (ops->trampoline) {
/*
@@ -848,11 +852,14 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
*/
if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
return;
+ npages = PAGE_ALIGN(ops->trampoline_size) >> PAGE_SHIFT;
+ set_memory_rw(ops->trampoline, npages);
} else {
ops->trampoline = create_trampoline(ops, &size);
if (!ops->trampoline)
return;
ops->trampoline_size = size;
+ npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
}
offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS);
@@ -863,6 +870,7 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
/* Do a safe modify in case the trampoline is executing */
new = ftrace_call_replace(ip, (unsigned long)func);
ret = update_ftrace_func(ip, new);
+ set_memory_ro(ops->trampoline, npages);
/* The update should never fail */
WARN_ON(ret);
@@ -939,7 +947,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
return;
- tramp_free((void *)ops->trampoline);
+ tramp_free((void *)ops->trampoline, ops->trampoline_size);
ops->trampoline = 0;
}
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 5b2bbfbb3712..6b877807598b 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -52,6 +52,7 @@
#include <linux/ftrace.h>
#include <linux/frame.h>
#include <linux/kasan.h>
+#include <linux/moduleloader.h>
#include <asm/text-patching.h>
#include <asm/cacheflush.h>
@@ -417,6 +418,14 @@ static void prepare_boost(struct kprobe *p, struct insn *insn)
}
}
+/* Recover page to RW mode before releasing it */
+void free_insn_page(void *page)
+{
+ set_memory_nx((unsigned long)page & PAGE_MASK, 1);
+ set_memory_rw((unsigned long)page & PAGE_MASK, 1);
+ module_memfree(page);
+}
+
static int arch_copy_kprobe(struct kprobe *p)
{
struct insn insn;
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 1dcd2be4cce4..c8520b2c62d2 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -186,7 +186,7 @@ static void cpa_flush_range(unsigned long start, int numpages, int cache)
unsigned int i, level;
unsigned long addr;
- BUG_ON(irqs_disabled());
+ BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
WARN_ON(PAGE_ALIGN(start) != start);
on_each_cpu(__cpa_flush_range, NULL, 1);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2d2d3a568e4e..adfe3b4cfe05 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -122,7 +122,7 @@ static void *alloc_insn_page(void)
return module_alloc(PAGE_SIZE);
}
-static void free_insn_page(void *page)
+void __weak free_insn_page(void *page)
{
module_memfree(page);
}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 74fdfe9ed3db..9e5841dc14b5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5063,7 +5063,7 @@ ftrace_graph_release(struct inode *inode, struct file *file)
}
out:
- kfree(fgd->new_hash);
+ free_ftrace_hash(fgd->new_hash);
kfree(fgd);
return ret;
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
new file mode 100644
index 000000000000..f4d1ff785d67
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
@@ -0,0 +1,21 @@
+#!/bin/sh
+# description: Register/unregister many kprobe events
+
+# ftrace fentry skip size depends on the machine architecture.
+# Currently HAVE_KPROBES_ON_FTRACE defined on x86 and powerpc
+case `uname -m` in
+ x86_64|i[3456]86) OFFS=5;;
+ ppc*) OFFS=4;;
+ *) OFFS=0;;
+esac
+
+echo "Setup up to 256 kprobes"
+grep t /proc/kallsyms | cut -f3 -d" " | grep -v .*\\..* | \
+head -n 256 | while read i; do echo p ${i}+${OFFS} ; done > kprobe_events ||:
+
+echo 1 > events/kprobes/enable
+echo 0 > events/kprobes/enable
+echo > kprobe_events
+echo "Waiting for unoptimizing & freeing"
+sleep 5
+echo "Done"