diff --git a/Makefile b/Makefile
index f4773aee95c4..0e14a3a30d07 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
VERSION = 5
PATCHLEVEL = 14
-SUBLEVEL = 19
+SUBLEVEL = 20
EXTRAVERSION =
NAME = Opossums on Parade
diff --git a/arch/alpha/include/asm/processor.h b/arch/alpha/include/asm/processor.h
index 090499c99c1c..6100431da07a 100644
--- a/arch/alpha/include/asm/processor.h
+++ b/arch/alpha/include/asm/processor.h
@@ -42,7 +42,7 @@ extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
struct task_struct;
extern void release_thread(struct task_struct *);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index 5f8527081da9..a5123ea426ce 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -376,11 +376,12 @@ thread_saved_pc(struct task_struct *t)
}
unsigned long
-__get_wchan(struct task_struct *p)
+get_wchan(struct task_struct *p)
{
unsigned long schedule_frame;
unsigned long pc;
-
+ if (!p || p == current || task_is_running(p))
+ return 0;
/*
* This one depends on the frame size of schedule(). Do a
* "disass schedule" in gdb to find the frame size. Also, the
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 04a5268e592b..e4031ecd3c8c 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -70,7 +70,7 @@ struct task_struct;
extern void start_thread(struct pt_regs * regs, unsigned long pc,
unsigned long usp);
-extern unsigned int __get_wchan(struct task_struct *p);
+extern unsigned int get_wchan(struct task_struct *p);
#endif /* !__ASSEMBLY__ */
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index db96cc878389..1b9576d21e24 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -15,7 +15,7 @@
* = specifics of data structs where trace is saved(CONFIG_STACKTRACE etc)
*
* vineetg: March 2009
- * -Implemented correct versions of thread_saved_pc() and __get_wchan()
+ * -Implemented correct versions of thread_saved_pc() and get_wchan()
*
* rajeshwarr: 2008
* -Initial implementation
@@ -248,7 +248,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
* Of course just returning schedule( ) would be pointless so unwind until
* the function is not in schedular code
*/
-unsigned int __get_wchan(struct task_struct *tsk)
+unsigned int get_wchan(struct task_struct *tsk)
{
return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL);
}
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 6af68edfa53a..9e6b97286307 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -84,7 +84,7 @@ struct task_struct;
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 261be96fa0c3..fc9e8b37eaa8 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -283,11 +283,13 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
return 0;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;
unsigned long stack_page;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
frame.fp = thread_saved_fp(p);
frame.sp = thread_saved_sp(p);
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 922355eb7eef..b6517fd03d7b 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -251,7 +251,7 @@ struct task_struct;
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
void set_task_sctlr_el1(u64 sctlr);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 46995c972ff5..c858b857c1ec 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -544,11 +544,13 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
return last;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;
unsigned long stack_page, ret = 0;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
stack_page = (unsigned long)try_get_task_stack(p);
if (!stack_page)
diff --git a/arch/csky/include/asm/processor.h b/arch/csky/include/asm/processor.h
index 817dd60ff152..9e933021fe8e 100644
--- a/arch/csky/include/asm/processor.h
+++ b/arch/csky/include/asm/processor.h
@@ -81,7 +81,7 @@ static inline void release_thread(struct task_struct *dead_task)
extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->usp)
diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c
index 9f78f5d21511..1b280ef08004 100644
--- a/arch/csky/kernel/stacktrace.c
+++ b/arch/csky/kernel/stacktrace.c
@@ -111,11 +111,12 @@ static bool save_wchan(unsigned long pc, void *arg)
return false;
}
-unsigned long __get_wchan(struct task_struct *task)
+unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc = 0;
- walk_stackframe(task, NULL, save_wchan, &pc);
+ if (likely(task && task != current && !task_is_running(task)))
+ walk_stackframe(task, NULL, save_wchan, &pc);
return pc;
}
diff --git a/arch/h8300/include/asm/processor.h b/arch/h8300/include/asm/processor.h
index 141a23eb62b7..a060b41b2d31 100644
--- a/arch/h8300/include/asm/processor.h
+++ b/arch/h8300/include/asm/processor.h
@@ -105,7 +105,7 @@ static inline void release_thread(struct task_struct *dead_task)
{
}
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) \
({ \
diff --git a/arch/h8300/kernel/process.c b/arch/h8300/kernel/process.c
index 8833fa4f5d51..2ac27e4248a4 100644
--- a/arch/h8300/kernel/process.c
+++ b/arch/h8300/kernel/process.c
@@ -128,12 +128,15 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
return 0;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
stack_page = (unsigned long)p;
fp = ((struct pt_regs *)p->thread.ksp)->er6;
do {
diff --git a/arch/hexagon/include/asm/processor.h b/arch/hexagon/include/asm/processor.h
index 615f7e49968e..9f0cc99420be 100644
--- a/arch/hexagon/include/asm/processor.h
+++ b/arch/hexagon/include/asm/processor.h
@@ -64,7 +64,7 @@ struct thread_struct {
extern void release_thread(struct task_struct *dead_task);
/* Get wait channel for task P. */
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
/* The following stuff is pretty HEXAGON specific. */
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c
index 232dfd8956aa..6a6835fb4242 100644
--- a/arch/hexagon/kernel/process.c
+++ b/arch/hexagon/kernel/process.c
@@ -130,11 +130,13 @@ void flush_thread(void)
* is an identification of the point at which the scheduler
* was invoked by a blocked thread.
*/
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
stack_page = (unsigned long)task_stack_page(p);
fp = ((struct hexagon_switch_stack *)p->thread.switch_sp)->fp;
diff --git a/arch/ia64/include/asm/processor.h b/arch/ia64/include/asm/processor.h
index 45365c2ef598..2d8bcdc27d7f 100644
--- a/arch/ia64/include/asm/processor.h
+++ b/arch/ia64/include/asm/processor.h
@@ -330,7 +330,7 @@ struct task_struct;
#define release_thread(dead_task)
/* Get wait channel for task P. */
-extern unsigned long __get_wchan (struct task_struct *p);
+extern unsigned long get_wchan (struct task_struct *p);
/* Return instruction pointer of blocked task TSK. */
#define KSTK_EIP(tsk) \
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 834df24a88f1..e56d63f4abf9 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -523,12 +523,15 @@ exit_thread (struct task_struct *tsk)
}
unsigned long
-__get_wchan (struct task_struct *p)
+get_wchan (struct task_struct *p)
{
struct unw_frame_info info;
unsigned long ip;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
/*
* Note: p may not be a blocked task (it could be current or
* another process running on some other CPU. Rather than
diff --git a/arch/m68k/include/asm/processor.h b/arch/m68k/include/asm/processor.h
index bacec548cb3c..3750819ac5a1 100644
--- a/arch/m68k/include/asm/processor.h
+++ b/arch/m68k/include/asm/processor.h
@@ -125,7 +125,7 @@ static inline void release_thread(struct task_struct *dead_task)
{
}
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) \
({ \
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index d2357cba09ab..db49f9091711 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -263,11 +263,13 @@ int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
}
EXPORT_SYMBOL(dump_fpu);
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
stack_page = (unsigned long)task_stack_page(p);
fp = ((struct switch_stack *)p->thread.ksp)->a6;
diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
index 7e9e92670df3..06c6e493590a 100644
--- a/arch/microblaze/include/asm/processor.h
+++ b/arch/microblaze/include/asm/processor.h
@@ -68,7 +68,7 @@ static inline void release_thread(struct task_struct *dead_task)
{
}
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
/* The size allocated for kernel stacks. This _must_ be a power of two! */
# define KERNEL_STACK_SIZE 0x2000
diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 5e2b91c1e8ce..62aa237180b6 100644
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -112,7 +112,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
return 0;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
/* TBD (used by procfs) */
return 0;
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 252ed38ce8c5..0c3550c82b72 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -369,7 +369,7 @@ static inline void flush_thread(void)
{
}
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \
THREAD_SIZE - 32 - sizeof(struct pt_regs))
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 637e6207e350..73c8e7990a97 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -511,7 +511,7 @@ static int __init frame_info_init(void)
/*
* Without schedule() frame info, result given by
- * thread_saved_pc() and __get_wchan() are not reliable.
+ * thread_saved_pc() and get_wchan() are not reliable.
*/
if (schedule_mfi.pc_offset < 0)
printk("Can't analyze schedule() prologue at %p\n", schedule);
@@ -652,9 +652,9 @@ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
#endif
/*
- * __get_wchan - a maintenance nightmare^W^Wpain in the ass ...
+ * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
*/
-unsigned long __get_wchan(struct task_struct *task)
+unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc = 0;
#ifdef CONFIG_KALLSYMS
@@ -662,6 +662,8 @@ unsigned long __get_wchan(struct task_struct *task)
unsigned long ra = 0;
#endif
+ if (!task || task == current || task_is_running(task))
+ goto out;
if (!task_stack_page(task))
goto out;
diff --git a/arch/nds32/include/asm/processor.h b/arch/nds32/include/asm/processor.h
index e6bfc74972bb..b82369c7659d 100644
--- a/arch/nds32/include/asm/processor.h
+++ b/arch/nds32/include/asm/processor.h
@@ -83,7 +83,7 @@ extern struct task_struct *last_task_used_math;
/* Prepare to copy thread state - unlazy all lazy status */
#define prepare_to_copy(tsk) do { } while (0)
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define cpu_relax() barrier()
diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c
index 49fab9e39cbf..391895b54d13 100644
--- a/arch/nds32/kernel/process.c
+++ b/arch/nds32/kernel/process.c
@@ -233,12 +233,15 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
EXPORT_SYMBOL(dump_fpu);
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, lr;
unsigned long stack_start, stack_end;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
if (IS_ENABLED(CONFIG_FRAME_POINTER)) {
stack_start = (unsigned long)end_of_stack(p);
stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
@@ -255,3 +258,5 @@ unsigned long __get_wchan(struct task_struct *p)
}
return 0;
}
+
+EXPORT_SYMBOL(get_wchan);
diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h
index b8125dfbcad2..94bcb86f679f 100644
--- a/arch/nios2/include/asm/processor.h
+++ b/arch/nios2/include/asm/processor.h
@@ -69,7 +69,7 @@ static inline void release_thread(struct task_struct *dead_task)
{
}
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1)
diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
index f8ea522a1588..9ff37ba2bb60 100644
--- a/arch/nios2/kernel/process.c
+++ b/arch/nios2/kernel/process.c
@@ -217,12 +217,15 @@ void dump(struct pt_regs *fp)
pr_emerg("\n\n");
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
stack_page = (unsigned long)p;
fp = ((struct switch_stack *)p->thread.ksp)->fp; /* ;dgt2 */
do {
diff --git a/arch/openrisc/include/asm/processor.h b/arch/openrisc/include/asm/processor.h
index aa1699c18add..ad53b3184885 100644
--- a/arch/openrisc/include/asm/processor.h
+++ b/arch/openrisc/include/asm/processor.h
@@ -73,7 +73,7 @@ struct thread_struct {
void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp);
void release_thread(struct task_struct *);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define cpu_relax() barrier()
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index eeea6d54b198..eb62429681fc 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -265,7 +265,7 @@ void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
dest[35] = 0;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
/* TODO */
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index 5e5ceb5b9631..b5fbcd2c1780 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -277,7 +277,7 @@ struct mm_struct;
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) ((tsk)->thread.regs.iaoq[0])
#define KSTK_ESP(tsk) ((tsk)->thread.regs.gr[30])
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 05e89d4fa911..184ec3c1eae4 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -243,12 +243,15 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
}
unsigned long
-__get_wchan(struct task_struct *p)
+get_wchan(struct task_struct *p)
{
struct unwind_frame_info info;
unsigned long ip;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
/*
* These bracket the sleeping functions..
*/
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index e39bd0ff69f3..f348e564f7dd 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -300,7 +300,7 @@ struct thread_struct {
#define task_pt_regs(tsk) ((tsk)->thread.regs)
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->nip: 0)
#define KSTK_ESP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->gpr[1]: 0)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 247ef0b9bfa4..185beb290580 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2111,11 +2111,14 @@ int validate_sp(unsigned long sp, struct task_struct *p,
EXPORT_SYMBOL(validate_sp);
-static unsigned long ___get_wchan(struct task_struct *p)
+static unsigned long __get_wchan(struct task_struct *p)
{
unsigned long ip, sp;
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
sp = p->thread.ksp;
if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
return 0;
@@ -2134,14 +2137,14 @@ static unsigned long ___get_wchan(struct task_struct *p)
return 0;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long ret;
if (!try_get_task_stack(p))
return 0;
- ret = ___get_wchan(p);
+ ret = __get_wchan(p);
put_task_stack(p);
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 086821b44def..021ed64ee608 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -58,7 +58,7 @@ static inline void release_thread(struct task_struct *dead_task)
{
}
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
static inline void wait_for_interrupt(void)
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index 0fcdc0233fac..315db3d0229b 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -128,14 +128,16 @@ static bool save_wchan(void *arg, unsigned long pc)
return true;
}
-unsigned long __get_wchan(struct task_struct *task)
+unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc = 0;
- if (!try_get_task_stack(task))
- return 0;
- walk_stackframe(task, NULL, save_wchan, &pc);
- put_task_stack(task);
+ if (likely(task && task != current && !task_is_running(task))) {
+ if (!try_get_task_stack(task))
+ return 0;
+ walk_stackframe(task, NULL, save_wchan, &pc);
+ put_task_stack(task);
+ }
return pc;
}
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index f54c152bf2bf..879b8e3f609c 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -192,7 +192,7 @@ static inline void release_thread(struct task_struct *tsk) { }
void guarded_storage_release(struct task_struct *tsk);
void gs_load_bc_cb(struct pt_regs *regs);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
#define task_pt_regs(tsk) ((struct pt_regs *) \
(task_stack_page(tsk) + THREAD_SIZE) - 1)
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->psw.addr)
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index e5dd46b1bff8..350e94d0cac2 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -181,12 +181,12 @@ void execve_tail(void)
asm volatile("sfpc %0" : : "d" (0));
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
struct unwind_state state;
unsigned long ip = 0;
- if (!task_stack_page(p))
+ if (!p || p == current || task_is_running(p) || !task_stack_page(p))
return 0;
if (!try_get_task_stack(p))
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index 45240ec6b85a..aa92cc933889 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -180,7 +180,7 @@ static inline void show_code(struct pt_regs *regs)
}
#endif
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[15])
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index 1c28e3cddb60..717de05c81f4 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -182,10 +182,13 @@ __switch_to(struct task_struct *prev, struct task_struct *next)
return prev;
}
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long pc;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
/*
* The same comment as on the Alpha applies here, too ...
*/
diff --git a/arch/sparc/include/asm/processor_32.h b/arch/sparc/include/asm/processor_32.h
index 647bf0ac7beb..b6242f7771e9 100644
--- a/arch/sparc/include/asm/processor_32.h
+++ b/arch/sparc/include/asm/processor_32.h
@@ -89,7 +89,7 @@ static inline void start_thread(struct pt_regs * regs, unsigned long pc,
/* Free all resources held by a thread. */
#define release_thread(tsk) do { } while(0)
-unsigned long __get_wchan(struct task_struct *);
+unsigned long get_wchan(struct task_struct *);
#define task_pt_regs(tsk) ((tsk)->thread.kregs)
#define KSTK_EIP(tsk) ((tsk)->thread.kregs->pc)
diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h
index ae851e8fce4c..5cf145f18f36 100644
--- a/arch/sparc/include/asm/processor_64.h
+++ b/arch/sparc/include/asm/processor_64.h
@@ -183,7 +183,7 @@ do { \
/* Free all resources held by a thread. */
#define release_thread(tsk) do { } while (0)
-unsigned long __get_wchan(struct task_struct *task);
+unsigned long get_wchan(struct task_struct *task);
#define task_pt_regs(tsk) (task_thread_info(tsk)->kregs)
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->tpc)
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 29a2f396f860..93983d6d431d 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -368,7 +368,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
return 0;
}
-unsigned long __get_wchan(struct task_struct *task)
+unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc, fp, bias = 0;
unsigned long task_base = (unsigned long) task;
@@ -376,6 +376,9 @@ unsigned long __get_wchan(struct task_struct *task)
struct reg_window32 *rw;
int count = 0;
+ if (!task || task == current || task_is_running(task))
+ goto out;
+
fp = task_thread_info(task)->ksp + bias;
do {
/* Bogus frame pointer? */
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index fa8db86e561c..d33c58a58d4f 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -666,7 +666,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
return 0;
}
-unsigned long __get_wchan(struct task_struct *task)
+unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc, fp, bias = 0;
struct thread_info *tp;
@@ -674,6 +674,9 @@ unsigned long __get_wchan(struct task_struct *task)
unsigned long ret = 0;
int count = 0;
+ if (!task || task == current || task_is_running(task))
+ goto out;
+
tp = task_thread_info(task);
bias = STACK_BIAS;
fp = task_thread_info(task)->ksp + bias;
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index 579692a40a55..b5cf0ed116d9 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -106,6 +106,6 @@ extern struct cpuinfo_um boot_cpu_data;
#define cache_line_size() (boot_cpu_data.cache_alignment)
#define KSTK_REG(tsk, reg) get_thread_reg(reg, &tsk->thread.switch_buf)
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
#endif
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 82107373ac7e..457a38db368b 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -364,11 +364,14 @@ unsigned long arch_align_stack(unsigned long sp)
}
#endif
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack_page, sp, ip;
bool seen_sched = 0;
+ if ((p == NULL) || (p == current) || task_is_running(p))
+ return 0;
+
stack_page = (unsigned long) task_stack_page(p);
/* Bail if the process has no kernel stack for some reason */
if (stack_page == 0)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6f9ed2e800f2..d2c11378c783 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -588,7 +588,7 @@ static inline void load_sp0(unsigned long sp0)
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
-unsigned long __get_wchan(struct task_struct *p);
+unsigned long get_wchan(struct task_struct *p);
/*
* Generic CPUID function
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 2fe1810e922a..f2f733bcb2b9 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -43,7 +43,6 @@
#include <asm/io_bitmap.h>
#include <asm/proto.h>
#include <asm/frame.h>
-#include <asm/unwind.h>
#include "process.h"
@@ -944,22 +943,60 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
* because the task might wake up and we might look at a stack
* changing under us.
*/
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
- struct unwind_state state;
- unsigned long addr = 0;
+ unsigned long start, bottom, top, sp, fp, ip, ret = 0;
+ int count = 0;
- for (unwind_start(&state, p, NULL, NULL); !unwind_done(&state);
- unwind_next_frame(&state)) {
- addr = unwind_get_return_address(&state);
- if (!addr)
- break;
- if (in_sched_functions(addr))
- continue;
- break;
- }
+ if (p == current || task_is_running(p))
+ return 0;
+
+ if (!try_get_task_stack(p))
+ return 0;
+
+ start = (unsigned long)task_stack_page(p);
+ if (!start)
+ goto out;
+
+ /*
+ * Layout of the stack page:
+ *
+ * ----------- topmax = start + THREAD_SIZE - sizeof(unsigned long)
+ * PADDING
+ * ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING
+ * stack
+ * ----------- bottom = start
+ *
+ * The tasks stack pointer points at the location where the
+ * framepointer is stored. The data on the stack is:
+ * ... IP FP ... IP FP
+ *
+ * We need to read FP and IP, so we need to adjust the upper
+ * bound by another unsigned long.
+ */
+ top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;
+ top -= 2 * sizeof(unsigned long);
+ bottom = start;
+
+ sp = READ_ONCE(p->thread.sp);
+ if (sp < bottom || sp > top)
+ goto out;
+
+ fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp);
+ do {
+ if (fp < bottom || fp > top)
+ goto out;
+ ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long)));
+ if (!in_sched_functions(ip)) {
+ ret = ip;
+ goto out;
+ }
+ fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
+ } while (count++ < 16 && !task_is_running(p));
- return addr;
+out:
+ put_task_stack(p);
+ return ret;
}
long do_arch_prctl_common(struct task_struct *task, int option,
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index ad15fbc57283..7f63aca6a0d3 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -215,7 +215,7 @@ struct mm_struct;
/* Free all resources held by a thread. */
#define release_thread(thread) do { } while(0)
-extern unsigned long __get_wchan(struct task_struct *p);
+extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
index 47f933fed870..060165340612 100644
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -298,12 +298,15 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
* These bracket the sleeping functions..
*/
-unsigned long __get_wchan(struct task_struct *p)
+unsigned long get_wchan(struct task_struct *p)
{
unsigned long sp, pc;
unsigned long stack_page = (unsigned long) task_stack_page(p);
int count = 0;
+ if (!p || p == current || task_is_running(p))
+ return 0;
+
sp = p->thread.sp;
pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4ee118cf0697..8e10c7accdbc 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2030,7 +2030,6 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
#endif /* CONFIG_SMP */
extern bool sched_task_on_rq(struct task_struct *p);
-extern unsigned long get_wchan(struct task_struct *p);
/*
* In order to reduce various lock holder preemption latencies provide an
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5ea5b6d8b2a9..9289da7f0ac4 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1960,25 +1960,6 @@ bool sched_task_on_rq(struct task_struct *p)
return task_on_rq_queued(p);
}
-unsigned long get_wchan(struct task_struct *p)
-{
- unsigned long ip = 0;
- unsigned int state;
-
- if (!p || p == current)
- return 0;
-
- /* Only get wchan if task is blocked and we can keep it that way. */
- raw_spin_lock_irq(&p->pi_lock);
- state = READ_ONCE(p->__state);
- smp_rmb(); /* see try_to_wake_up() */
- if (state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq)
- ip = __get_wchan(p);
- raw_spin_unlock_irq(&p->pi_lock);
-
- return ip;
-}
-
static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
{
if (!(flags & ENQUEUE_NOCLOCK))
