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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 13:11:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 13:11:48 -0700
commit2c6a392cddacde153865b15e8295ad0a35ed3c02 (patch)
tree558c34595f8987c87d26fc0fa0dc644fca9ef2cd /arch
parent0a499fc5c37e6db096969a83534fd98a2bf2b36c (diff)
parent3599fe12a125fa7118da2bcc5033d7741fb5f3a1 (diff)
Merge branch 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull stack trace updates from Ingo Molnar: "So Thomas looked at the stacktrace code recently and noticed a few weirdnesses, and we all know how such stories of crummy kernel code meeting German engineering perfection end: a 45-patch series to clean it all up! :-) Here's the changes in Thomas's words: 'Struct stack_trace is a sinkhole for input and output parameters which is largely pointless for most usage sites. In fact if embedded into other data structures it creates indirections and extra storage overhead for no benefit. Looking at all usage sites makes it clear that they just require an interface which is based on a storage array. That array is either on stack, global or embedded into some other data structure. Some of the stack depot usage sites are outright wrong, but fortunately the wrongness just causes more stack being used for nothing and does not have functional impact. Another oddity is the inconsistent termination of the stack trace with ULONG_MAX. It's pointless as the number of entries is what determines the length of the stored trace. In fact quite some call sites remove the ULONG_MAX marker afterwards with or without nasty comments about it. Not all architectures do that and those which do, do it inconsistenly either conditional on nr_entries == 0 or unconditionally. The following series cleans that up by: 1) Removing the ULONG_MAX termination in the architecture code 2) Removing the ULONG_MAX fixups at the call sites 3) Providing plain storage array based interfaces for stacktrace and stackdepot. 4) Cleaning up the mess at the callsites including some related cleanups. 5) Removing the struct stack_trace based interfaces This is not changing the struct stack_trace interfaces at the architecture level, but it removes the exposure to the generic code'" * 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) x86/stacktrace: Use common infrastructure stacktrace: Provide common infrastructure lib/stackdepot: Remove obsolete functions stacktrace: Remove obsolete functions livepatch: Simplify stack trace retrieval tracing: Remove the last struct stack_trace usage tracing: Simplify stack trace retrieval tracing: Make ftrace_trace_userstack() static and conditional tracing: Use percpu stack trace buffer more intelligently tracing: Simplify stacktrace retrieval in histograms lockdep: Simplify stack trace handling lockdep: Remove save argument from check_prev_add() lockdep: Remove unused trace argument from print_circular_bug() drm: Simplify stacktrace handling dm persistent data: Simplify stack trace handling dm bufio: Simplify stack trace retrieval btrfs: ref-verify: Simplify stack trace retrieval dma/debug: Simplify stracktrace retrieval fault-inject: Simplify stacktrace retrieval mm/page_owner: Simplify stack trace handling ...
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/kernel/stacktrace.c6
-rw-r--r--arch/arm64/kernel/stacktrace.c4
-rw-r--r--arch/parisc/kernel/stacktrace.c5
-rw-r--r--arch/riscv/kernel/stacktrace.c2
-rw-r--r--arch/s390/kernel/stacktrace.c6
-rw-r--r--arch/sh/kernel/stacktrace.c4
-rw-r--r--arch/um/kernel/stacktrace.c2
-rw-r--r--arch/unicore32/kernel/stacktrace.c2
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/kernel/stacktrace.c128
10 files changed, 21 insertions, 139 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index a56e7c856ab5..86870f40f9a0 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -115,8 +115,6 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
* running on another CPU? For now, ignore it as we
* can't guarantee we won't explode.
*/
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
return;
#else
frame.fp = thread_saved_fp(tsk);
@@ -134,8 +132,6 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
}
walk_stackframe(&frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
@@ -153,8 +149,6 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
frame.pc = regs->ARM_pc;
walk_stackframe(&frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index d908b5e9e949..b00ec7d483d1 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -140,8 +140,6 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
#endif
walk_stackframe(current, &frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_regs);
@@ -172,8 +170,6 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
#endif
walk_stackframe(tsk, &frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
put_task_stack(tsk);
}
diff --git a/arch/parisc/kernel/stacktrace.c b/arch/parisc/kernel/stacktrace.c
index ec5835e83a7a..6f0b9c8d8052 100644
--- a/arch/parisc/kernel/stacktrace.c
+++ b/arch/parisc/kernel/stacktrace.c
@@ -29,22 +29,17 @@ static void dump_trace(struct task_struct *task, struct stack_trace *trace)
}
}
-
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace(struct stack_trace *trace)
{
dump_trace(current, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
dump_trace(tsk, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index a4b1d94371a0..4d403274c2e8 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -169,8 +169,6 @@ static bool save_trace(unsigned long pc, void *arg)
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
walk_stackframe(tsk, NULL, save_trace, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 460dcfba7d4e..cc9ed9787068 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -45,8 +45,6 @@ void save_stack_trace(struct stack_trace *trace)
sp = current_stack_pointer();
dump_trace(save_address, trace, NULL, sp);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);
@@ -58,8 +56,6 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
if (tsk == current)
sp = current_stack_pointer();
dump_trace(save_address_nosched, trace, tsk, sp);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
@@ -69,7 +65,5 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
sp = kernel_stack_pointer(regs);
dump_trace(save_address, trace, NULL, sp);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_regs);
diff --git a/arch/sh/kernel/stacktrace.c b/arch/sh/kernel/stacktrace.c
index f3cb2cccb262..2950b19ad077 100644
--- a/arch/sh/kernel/stacktrace.c
+++ b/arch/sh/kernel/stacktrace.c
@@ -49,8 +49,6 @@ void save_stack_trace(struct stack_trace *trace)
unsigned long *sp = (unsigned long *)current_stack_pointer;
unwind_stack(current, NULL, sp, &save_stack_ops, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);
@@ -84,7 +82,5 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
unsigned long *sp = (unsigned long *)tsk->thread.sp;
unwind_stack(current, NULL, sp, &save_stack_ops_nosched, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
diff --git a/arch/um/kernel/stacktrace.c b/arch/um/kernel/stacktrace.c
index ebe7bcf62684..bd95e020d509 100644
--- a/arch/um/kernel/stacktrace.c
+++ b/arch/um/kernel/stacktrace.c
@@ -63,8 +63,6 @@ static const struct stacktrace_ops dump_ops = {
static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
{
dump_trace(tsk, &dump_ops, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace(struct stack_trace *trace)
diff --git a/arch/unicore32/kernel/stacktrace.c b/arch/unicore32/kernel/stacktrace.c
index 9976e767d51c..e37da8c6837b 100644
--- a/arch/unicore32/kernel/stacktrace.c
+++ b/arch/unicore32/kernel/stacktrace.c
@@ -120,8 +120,6 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
}
walk_stackframe(&frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace(struct stack_trace *trace)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 406a0cf30c57..f1162df4a805 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -74,6 +74,7 @@ config X86
select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
+ select ARCH_STACKWALK
select ARCH_SUPPORTS_ACPI
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 5c2d71a1dc06..2abf27d7df6b 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -12,78 +12,31 @@
#include <asm/stacktrace.h>
#include <asm/unwind.h>
-static int save_stack_address(struct stack_trace *trace, unsigned long addr,
- bool nosched)
-{
- if (nosched && in_sched_functions(addr))
- return 0;
-
- if (trace->skip > 0) {
- trace->skip--;
- return 0;
- }
-
- if (trace->nr_entries >= trace->max_entries)
- return -1;
-
- trace->entries[trace->nr_entries++] = addr;
- return 0;
-}
-
-static void noinline __save_stack_trace(struct stack_trace *trace,
- struct task_struct *task, struct pt_regs *regs,
- bool nosched)
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+ struct task_struct *task, struct pt_regs *regs)
{
struct unwind_state state;
unsigned long addr;
- if (regs)
- save_stack_address(trace, regs->ip, nosched);
+ if (regs && !consume_entry(cookie, regs->ip, false))
+ return;
for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
unwind_next_frame(&state)) {
addr = unwind_get_return_address(&state);
- if (!addr || save_stack_address(trace, addr, nosched))
+ if (!addr || !consume_entry(cookie, addr, false))
break;
}
-
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
/*
- * Save stack-backtrace addresses into a stack_trace buffer.
+ * 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.
*/
-void save_stack_trace(struct stack_trace *trace)
-{
- trace->skip++;
- __save_stack_trace(trace, current, NULL, false);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace);
-
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
- __save_stack_trace(trace, current, regs, false);
-}
-
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
-{
- if (!try_get_task_stack(tsk))
- return;
-
- if (tsk == current)
- trace->skip++;
- __save_stack_trace(trace, tsk, NULL, true);
-
- put_task_stack(tsk);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
-
-#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
-
-static int __always_inline
-__save_stack_trace_reliable(struct stack_trace *trace,
- struct task_struct *task)
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+ void *cookie, struct task_struct *task)
{
struct unwind_state state;
struct pt_regs *regs;
@@ -97,7 +50,7 @@ __save_stack_trace_reliable(struct stack_trace *trace,
if (regs) {
/* Success path for user tasks */
if (user_mode(regs))
- goto success;
+ return 0;
/*
* Kernel mode registers on the stack indicate an
@@ -120,7 +73,7 @@ __save_stack_trace_reliable(struct stack_trace *trace,
if (!addr)
return -EINVAL;
- if (save_stack_address(trace, addr, false))
+ if (!consume_entry(cookie, addr, false))
return -EINVAL;
}
@@ -132,39 +85,9 @@ __save_stack_trace_reliable(struct stack_trace *trace,
if (!(task->flags & (PF_KTHREAD | PF_IDLE)))
return -EINVAL;
-success:
- 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 the task doesn't have a stack (e.g., a zombie), the stack is
- * "reliably" empty.
- */
- if (!try_get_task_stack(tsk))
- return 0;
-
- 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 {
@@ -189,15 +112,15 @@ copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
return ret;
}
-static inline void __save_stack_trace_user(struct stack_trace *trace)
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+ const struct pt_regs *regs)
{
- const struct pt_regs *regs = task_pt_regs(current);
const void __user *fp = (const void __user *)regs->bp;
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = regs->ip;
+ if (!consume_entry(cookie, regs->ip, false))
+ return;
- while (trace->nr_entries < trace->max_entries) {
+ while (1) {
struct stack_frame_user frame;
frame.next_fp = NULL;
@@ -207,8 +130,8 @@ static inline void __save_stack_trace_user(struct stack_trace *trace)
if ((unsigned long)fp < regs->sp)
break;
if (frame.ret_addr) {
- trace->entries[trace->nr_entries++] =
- frame.ret_addr;
+ if (!consume_entry(cookie, frame.ret_addr, false))
+ return;
}
if (fp == frame.next_fp)
break;
@@ -216,14 +139,3 @@ static inline void __save_stack_trace_user(struct stack_trace *trace)
}
}
-void save_stack_trace_user(struct stack_trace *trace)
-{
- /*
- * Trace user stack if we are not a kernel thread
- */
- if (current->mm) {
- __save_stack_trace_user(trace);
- }
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
-}