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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 04:24:16 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 04:24:16 +0300
commit76f1948a79b26d5f57a5ee9941876b745c6baaea (patch)
treea2c42578e31acabc61db2115d91e467cea439cd7 /arch
parent7af4c727c7b6104f94f2ffc3d0899e75a9cc1e55 (diff)
parenta0841609f658c77f066af9c61a2e13143564fcb4 (diff)
downloadlinux-76f1948a79b26d5f57a5ee9941876b745c6baaea.tar.xz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatch updates from Jiri Kosina: - a per-task consistency model is being added for architectures that support reliable stack dumping (extending this, currently rather trivial set, is currently in the works). This extends the nature of the types of patches that can be applied by live patching infrastructure. The code stems from the design proposal made [1] back in November 2014. It's a hybrid of SUSE's kGraft and RH's kpatch, combining advantages of both: it uses kGraft's per-task consistency and syscall barrier switching combined with kpatch's stack trace switching. There are also a number of fallback options which make it quite flexible. Most of the heavy lifting done by Josh Poimboeuf with help from Miroslav Benes and Petr Mladek [1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz - module load time patch optimization from Zhou Chengming - a few assorted small fixes * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching: livepatch: add missing printk newlines livepatch: Cancel transition a safe way for immediate patches livepatch: Reduce the time of finding module symbols livepatch: make klp_mutex proper part of API livepatch: allow removal of a disabled patch livepatch: add /proc/<pid>/patch_state livepatch: change to a per-task consistency model livepatch: store function sizes livepatch: use kstrtobool() in enabled_store() livepatch: move patching functions into patch.c livepatch: remove unnecessary object loaded check livepatch: separate enabled and patched states livepatch/s390: add TIF_PATCH_PENDING thread flag livepatch/s390: reorganize TIF thread flag bits livepatch/powerpc: add TIF_PATCH_PENDING thread flag livepatch/x86: add TIF_PATCH_PENDING thread flag livepatch: create temporary klp_update_patch_state() stub x86/entry: define _TIF_ALLWORK_MASK flags explicitly stacktrace/x86: add function for detecting reliable stack traces
Diffstat (limited to 'arch')
-rw-r--r--arch/Kconfig6
-rw-r--r--arch/powerpc/include/asm/thread_info.h4
-rw-r--r--arch/powerpc/kernel/signal.c4
-rw-r--r--arch/s390/include/asm/thread_info.h24
-rw-r--r--arch/s390/kernel/entry.S30
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/entry/common.c9
-rw-r--r--arch/x86/include/asm/thread_info.h13
-rw-r--r--arch/x86/include/asm/unwind.h6
-rw-r--r--arch/x86/kernel/stacktrace.c96
-rw-r--r--arch/x86/kernel/unwind_frame.c2
11 files changed, 175 insertions, 20 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index c4d6833aacd9..640999412d11 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -720,6 +720,12 @@ config HAVE_STACK_VALIDATION
Architecture supports the 'objtool check' host tool command, which
performs compile-time stack metadata validation.
+config HAVE_RELIABLE_STACKTRACE
+ bool
+ help
+ Architecture has a save_stack_trace_tsk_reliable() function which
+ only returns a stack trace if it can guarantee the trace is reliable.
+
config HAVE_ARCH_HASH
bool
default n
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 87e4b2d8dcd4..6fc6464f7421 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -92,6 +92,7 @@ static inline struct thread_info *current_thread_info(void)
TIF_NEED_RESCHED */
#define TIF_32BIT 4 /* 32 bit binary */
#define TIF_RESTORE_TM 5 /* need to restore TM FP/VEC/VSX */
+#define TIF_PATCH_PENDING 6 /* pending live patching update */
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SINGLESTEP 8 /* singlestepping active */
#define TIF_NOHZ 9 /* in adaptive nohz mode */
@@ -115,6 +116,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_32BIT (1<<TIF_32BIT)
#define _TIF_RESTORE_TM (1<<TIF_RESTORE_TM)
+#define _TIF_PATCH_PENDING (1<<TIF_PATCH_PENDING)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
@@ -131,7 +133,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_RESUME | _TIF_UPROBE | \
- _TIF_RESTORE_TM)
+ _TIF_RESTORE_TM | _TIF_PATCH_PENDING)
#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
/* Bits in local_flags */
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 3a3671172436..e9436c5e1e09 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -14,6 +14,7 @@
#include <linux/uprobes.h>
#include <linux/key.h>
#include <linux/context_tracking.h>
+#include <linux/livepatch.h>
#include <asm/hw_breakpoint.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
@@ -162,6 +163,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
tracehook_notify_resume(regs);
}
+ if (thread_info_flags & _TIF_PATCH_PENDING)
+ klp_update_patch_state(current);
+
user_enter();
}
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index f36e6e2b73f0..0b3ee083a665 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -51,15 +51,14 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
/*
* thread information flags bit numbers
*/
+/* _TIF_WORK bits */
#define TIF_NOTIFY_RESUME 0 /* callback before returning to user */
#define TIF_SIGPENDING 1 /* signal pending */
#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
#define TIF_UPROBE 3 /* breakpointed or single-stepping */
#define TIF_GUARDED_STORAGE 4 /* load guarded storage control block */
-#define TIF_SYSCALL_TRACE 8 /* syscall trace active */
-#define TIF_SYSCALL_AUDIT 9 /* syscall auditing active */
-#define TIF_SECCOMP 10 /* secure computing */
-#define TIF_SYSCALL_TRACEPOINT 11 /* syscall tracepoint instrumentation */
+#define TIF_PATCH_PENDING 5 /* pending live patching update */
+
#define TIF_31BIT 16 /* 32bit process */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal() */
@@ -67,16 +66,25 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
#define TIF_BLOCK_STEP 20 /* This task is block stepped */
#define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */
+/* _TIF_TRACE bits */
+#define TIF_SYSCALL_TRACE 24 /* syscall trace active */
+#define TIF_SYSCALL_AUDIT 25 /* syscall auditing active */
+#define TIF_SECCOMP 26 /* secure computing */
+#define TIF_SYSCALL_TRACEPOINT 27 /* syscall tracepoint instrumentation */
+
#define _TIF_NOTIFY_RESUME _BITUL(TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING _BITUL(TIF_SIGPENDING)
#define _TIF_NEED_RESCHED _BITUL(TIF_NEED_RESCHED)
+#define _TIF_UPROBE _BITUL(TIF_UPROBE)
+#define _TIF_GUARDED_STORAGE _BITUL(TIF_GUARDED_STORAGE)
+#define _TIF_PATCH_PENDING _BITUL(TIF_PATCH_PENDING)
+
+#define _TIF_31BIT _BITUL(TIF_31BIT)
+#define _TIF_SINGLE_STEP _BITUL(TIF_SINGLE_STEP)
+
#define _TIF_SYSCALL_TRACE _BITUL(TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT _BITUL(TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP _BITUL(TIF_SECCOMP)
#define _TIF_SYSCALL_TRACEPOINT _BITUL(TIF_SYSCALL_TRACEPOINT)
-#define _TIF_UPROBE _BITUL(TIF_UPROBE)
-#define _TIF_31BIT _BITUL(TIF_31BIT)
-#define _TIF_SINGLE_STEP _BITUL(TIF_SINGLE_STEP)
-#define _TIF_GUARDED_STORAGE _BITUL(TIF_GUARDED_STORAGE)
#endif /* _ASM_THREAD_INFO_H */
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index c6cf338c9327..a5f5d3bb3dbc 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -47,7 +47,7 @@ STACK_SIZE = 1 << STACK_SHIFT
STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
_TIF_WORK = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
- _TIF_UPROBE | _TIF_GUARDED_STORAGE)
+ _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING)
_TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
_TIF_SYSCALL_TRACEPOINT)
_CIF_WORK = (_CIF_MCCK_PENDING | _CIF_ASCE_PRIMARY | \
@@ -334,6 +334,11 @@ ENTRY(system_call)
jo .Lsysc_guarded_storage
TSTMSK __PT_FLAGS(%r11),_PIF_PER_TRAP
jo .Lsysc_singlestep
+#ifdef CONFIG_LIVEPATCH
+ TSTMSK __TI_flags(%r12),_TIF_PATCH_PENDING
+ jo .Lsysc_patch_pending # handle live patching just before
+ # signals and possible syscall restart
+#endif
TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
jo .Lsysc_sigpending
TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME
@@ -415,6 +420,15 @@ ENTRY(system_call)
lgr %r2,%r11 # pass pointer to pt_regs
larl %r14,.Lsysc_return
jg gs_load_bc_cb
+#
+# _TIF_PATCH_PENDING is set, call klp_update_patch_state
+#
+#ifdef CONFIG_LIVEPATCH
+.Lsysc_patch_pending:
+ lg %r2,__LC_CURRENT # pass pointer to task struct
+ larl %r14,.Lsysc_return
+ jg klp_update_patch_state
+#endif
#
# _PIF_PER_TRAP is set, call do_per_trap
@@ -667,6 +681,10 @@ ENTRY(io_int_handler)
jo .Lio_mcck_pending
TSTMSK __TI_flags(%r12),_TIF_NEED_RESCHED
jo .Lio_reschedule
+#ifdef CONFIG_LIVEPATCH
+ TSTMSK __TI_flags(%r12),_TIF_PATCH_PENDING
+ jo .Lio_patch_pending
+#endif
TSTMSK __TI_flags(%r12),_TIF_SIGPENDING
jo .Lio_sigpending
TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME
@@ -730,6 +748,16 @@ ENTRY(io_int_handler)
j .Lio_return
#
+# _TIF_PATCH_PENDING is set, call klp_update_patch_state
+#
+#ifdef CONFIG_LIVEPATCH
+.Lio_patch_pending:
+ lg %r2,__LC_CURRENT # pass pointer to task struct
+ larl %r14,.Lio_return
+ jg klp_update_patch_state
+#endif
+
+#
# _TIF_SIGPENDING or is set, call do_signal
#
.Lio_sigpending:
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8d4f87e5bba3..cd18994a9555 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -160,6 +160,7 @@ config X86
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_REGS_AND_STACK_ACCESS_API
+ select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER && STACK_VALIDATION
select HAVE_STACK_VALIDATION if X86_64
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UNSTABLE_SCHED_CLOCK
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 370c42c7f046..cdefcfdd9e63 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -22,6 +22,7 @@
#include <linux/context_tracking.h>
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
+#include <linux/livepatch.h>
#include <asm/desc.h>
#include <asm/traps.h>
@@ -130,14 +131,13 @@ static long syscall_trace_enter(struct pt_regs *regs)
#define EXIT_TO_USERMODE_LOOP_FLAGS \
(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
- _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY)
+ _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING)
static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
{
/*
* In order to return to user mode, we need to have IRQs off with
- * none of _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_USER_RETURN_NOTIFY,
- * _TIF_UPROBE, or _TIF_NEED_RESCHED set. Several of these flags
+ * none of EXIT_TO_USERMODE_LOOP_FLAGS set. Several of these flags
* can be set at any time on preemptable kernels if we have IRQs on,
* so we need to loop. Disabling preemption wouldn't help: doing the
* work to clear some of the flags can sleep.
@@ -164,6 +164,9 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
if (cached_flags & _TIF_USER_RETURN_NOTIFY)
fire_user_return_notifiers();
+ if (cached_flags & _TIF_PATCH_PENDING)
+ klp_update_patch_state(current);
+
/* Disable IRQs and retry */
local_irq_disable();
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index f765a49103fb..e00e1bd6e7b3 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -73,9 +73,6 @@ struct thread_info {
* thread information flags
* - these are process state flags that various assembly files
* may need to access
- * - pending work-to-be-done flags are in LSW
- * - other flags in MSW
- * Warning: layout of LSW is hardcoded in entry.S
*/
#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
@@ -87,6 +84,7 @@ struct thread_info {
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
#define TIF_UPROBE 12 /* breakpointed or singlestepping */
+#define TIF_PATCH_PENDING 13 /* pending live patching update */
#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* IA32 compatibility process */
@@ -104,13 +102,14 @@ struct thread_info {
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
-#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
+#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
#define _TIF_NOCPUID (1 << TIF_NOCPUID)
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
@@ -135,8 +134,10 @@ struct thread_info {
/* work to do on any return to user space */
#define _TIF_ALLWORK_MASK \
- ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \
- _TIF_NOHZ)
+ (_TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
+ _TIF_NEED_RESCHED | _TIF_SINGLESTEP | _TIF_SYSCALL_EMU | \
+ _TIF_SYSCALL_AUDIT | _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | \
+ _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT)
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW \
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index 9b10dcd51716..e6676495b125 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -11,6 +11,7 @@ struct unwind_state {
unsigned long stack_mask;
struct task_struct *task;
int graph_idx;
+ bool error;
#ifdef CONFIG_FRAME_POINTER
bool got_irq;
unsigned long *bp, *orig_sp;
@@ -42,6 +43,11 @@ void unwind_start(struct unwind_state *state, struct task_struct *task,
__unwind_start(state, task, regs, first_frame);
}
+static inline bool unwind_error(struct unwind_state *state)
+{
+ return state->error;
+}
+
#ifdef CONFIG_FRAME_POINTER
static inline
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 8e2b79b88e51..8dabd7bf1673 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -76,6 +76,101 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
+
+#define STACKTRACE_DUMP_ONCE(task) ({ \
+ static bool __section(.data.unlikely) __dumped; \
+ \
+ if (!__dumped) { \
+ __dumped = true; \
+ WARN_ON(1); \
+ show_stack(task, NULL); \
+ } \
+})
+
+static int __save_stack_trace_reliable(struct stack_trace *trace,
+ struct task_struct *task)
+{
+ struct unwind_state state;
+ struct pt_regs *regs;
+ unsigned long addr;
+
+ for (unwind_start(&state, task, NULL, NULL); !unwind_done(&state);
+ unwind_next_frame(&state)) {
+
+ regs = unwind_get_entry_regs(&state);
+ if (regs) {
+ /*
+ * Kernel mode registers on the stack indicate an
+ * in-kernel interrupt or exception (e.g., preemption
+ * or a page fault), which can make frame pointers
+ * unreliable.
+ */
+ if (!user_mode(regs))
+ return -EINVAL;
+
+ /*
+ * The last frame contains the user mode syscall
+ * pt_regs. Skip it and finish the unwind.
+ */
+ unwind_next_frame(&state);
+ if (!unwind_done(&state)) {
+ STACKTRACE_DUMP_ONCE(task);
+ return -EINVAL;
+ }
+ break;
+ }
+
+ addr = unwind_get_return_address(&state);
+
+ /*
+ * A NULL or invalid return address probably means there's some
+ * generated code which __kernel_text_address() doesn't know
+ * about.
+ */
+ if (!addr) {
+ STACKTRACE_DUMP_ONCE(task);
+ return -EINVAL;
+ }
+
+ if (save_stack_address(trace, addr, false))
+ return -EINVAL;
+ }
+
+ /* Check for stack corruption */
+ if (unwind_error(&state)) {
+ STACKTRACE_DUMP_ONCE(task);
+ return -EINVAL;
+ }
+
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+
+ return 0;
+}
+
+/*
+ * This function returns an error if it detects any unreliable features of the
+ * stack. Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int save_stack_trace_tsk_reliable(struct task_struct *tsk,
+ struct stack_trace *trace)
+{
+ int ret;
+
+ if (!try_get_task_stack(tsk))
+ return -EINVAL;
+
+ ret = __save_stack_trace_reliable(trace, tsk);
+
+ put_task_stack(tsk);
+
+ return ret;
+}
+#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */
+
/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
struct stack_frame_user {
@@ -138,4 +233,3 @@ void save_stack_trace_user(struct stack_trace *trace)
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
-
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index fec70fe3b1ec..82c6d7f1fd73 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -283,6 +283,8 @@ bool unwind_next_frame(struct unwind_state *state)
return true;
bad_address:
+ state->error = true;
+
/*
* When unwinding a non-current task, the task might actually be
* running on another CPU, in which case it could be modifying its