Revert "sched: Add wrapper for get_wchan() to keep task blocked"

This reverts commit e9ede14 which is commit 42a20f8 upstream. It has been reported to be causing problems, and is being reworked upstream and has been dropped from the current 5.15.y stable queue until it gets resolved. Reported-by: Chris Rankin <rankincj@gmail.com> Reported-by: Thorsten Leemhuis <linux@leemhuis.info> Link: https://lore.kernel.org/r/ed000478-2a60-0066-c337-a04bffc112b1@leemhuis.info Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kees Cook <keescook@chromium.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mariux64 · Nov 18, 2021 · 961913f · 961913f
1 parent b51c1a5
commit 961913f
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Showing 50 changed files with 112 additions and 80 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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);
@@ -652,16 +652,18 @@ 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
 	unsigned long sp;
 	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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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)