From: Kees Cook keescook@chromium.org
[ Upstream commit 42a20f86dc19f9282d974df0ba4d226c865ab9dd ]
Having a stable wchan means the process must be blocked and for it to stay that way while performing stack unwinding.
Suggested-by: Peter Zijlstra peterz@infradead.org Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Acked-by: Geert Uytterhoeven geert@linux-m68k.org Acked-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk [arm] Tested-by: Mark Rutland mark.rutland@arm.com [arm64] Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/alpha/include/asm/processor.h | 2 +- arch/alpha/kernel/process.c | 5 ++--- arch/arc/include/asm/processor.h | 2 +- arch/arc/kernel/stacktrace.c | 4 ++-- arch/arm/include/asm/processor.h | 2 +- arch/arm/kernel/process.c | 4 +--- arch/arm64/include/asm/processor.h | 2 +- arch/arm64/kernel/process.c | 4 +--- arch/csky/include/asm/processor.h | 2 +- arch/csky/kernel/stacktrace.c | 5 ++--- arch/h8300/include/asm/processor.h | 2 +- arch/h8300/kernel/process.c | 5 +---- arch/hexagon/include/asm/processor.h | 2 +- arch/hexagon/kernel/process.c | 4 +--- arch/ia64/include/asm/processor.h | 2 +- arch/ia64/kernel/process.c | 5 +---- arch/m68k/include/asm/processor.h | 2 +- arch/m68k/kernel/process.c | 4 +--- arch/microblaze/include/asm/processor.h | 2 +- arch/microblaze/kernel/process.c | 2 +- arch/mips/include/asm/processor.h | 2 +- arch/mips/kernel/process.c | 8 +++----- arch/nds32/include/asm/processor.h | 2 +- arch/nds32/kernel/process.c | 7 +------ arch/nios2/include/asm/processor.h | 2 +- arch/nios2/kernel/process.c | 5 +---- arch/openrisc/include/asm/processor.h | 2 +- arch/openrisc/kernel/process.c | 2 +- arch/parisc/include/asm/processor.h | 2 +- arch/parisc/kernel/process.c | 5 +---- arch/powerpc/include/asm/processor.h | 2 +- arch/powerpc/kernel/process.c | 9 +++------ arch/riscv/include/asm/processor.h | 2 +- arch/riscv/kernel/stacktrace.c | 12 +++++------- arch/s390/include/asm/processor.h | 2 +- arch/s390/kernel/process.c | 4 ++-- arch/sh/include/asm/processor_32.h | 2 +- arch/sh/kernel/process_32.c | 5 +---- arch/sparc/include/asm/processor_32.h | 2 +- arch/sparc/include/asm/processor_64.h | 2 +- arch/sparc/kernel/process_32.c | 5 +---- arch/sparc/kernel/process_64.c | 5 +---- arch/um/include/asm/processor-generic.h | 2 +- arch/um/kernel/process.c | 5 +---- arch/x86/include/asm/processor.h | 2 +- arch/x86/kernel/process.c | 5 +---- arch/xtensa/include/asm/processor.h | 2 +- arch/xtensa/kernel/process.c | 5 +---- include/linux/sched.h | 1 + kernel/sched/core.c | 19 +++++++++++++++++++ 50 files changed, 80 insertions(+), 112 deletions(-)
diff --git a/arch/alpha/include/asm/processor.h b/arch/alpha/include/asm/processor.h index 6100431da07a3..090499c99c1c1 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 a5123ea426ce5..5f8527081da92 100644 --- a/arch/alpha/kernel/process.c +++ b/arch/alpha/kernel/process.c @@ -376,12 +376,11 @@ 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 e4031ecd3c8c1..04a5268e592b9 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 1b9576d21e244..db96cc8783891 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 9e6b972863077..6af68edfa53ab 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 fc9e8b37eaa84..261be96fa0c30 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -283,13 +283,11 @@ 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 b6517fd03d7b6..922355eb7eefa 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 c858b857c1ecf..46995c972ff5f 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -544,13 +544,11 @@ __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 9e933021fe8e0..817dd60ff152d 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 1b280ef080045..9f78f5d215117 100644 --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -111,12 +111,11 @@ 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;
- if (likely(task && task != current && !task_is_running(task))) - walk_stackframe(task, NULL, save_wchan, &pc); + 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 a060b41b2d31c..141a23eb62b74 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 2ac27e4248a46..8833fa4f5d516 100644 --- a/arch/h8300/kernel/process.c +++ b/arch/h8300/kernel/process.c @@ -128,15 +128,12 @@ 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 9f0cc99420bee..615f7e49968e6 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 6a6835fb42425..232dfd8956aa2 100644 --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -130,13 +130,11 @@ 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 2d8bcdc27d7f8..45365c2ef5983 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 e56d63f4abf9d..834df24a88f12 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -523,15 +523,12 @@ 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 3750819ac5a13..bacec548cb3c6 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 db49f90917112..d2357cba09abe 100644 --- a/arch/m68k/kernel/process.c +++ b/arch/m68k/kernel/process.c @@ -263,13 +263,11 @@ 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 06c6e493590a2..7e9e92670df33 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 62aa237180b67..5e2b91c1e8ced 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 0c3550c82b726..252ed38ce8c5a 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 73c8e7990a973..637e6207e3500 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 @@ -662,8 +662,6 @@ 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 b82369c7659d4..e6bfc74972bb3 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 391895b54d13c..49fab9e39cbff 100644 --- a/arch/nds32/kernel/process.c +++ b/arch/nds32/kernel/process.c @@ -233,15 +233,12 @@ 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; @@ -258,5 +255,3 @@ 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 94bcb86f679f5..b8125dfbcad2d 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 9ff37ba2bb603..f8ea522a15880 100644 --- a/arch/nios2/kernel/process.c +++ b/arch/nios2/kernel/process.c @@ -217,15 +217,12 @@ 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 ad53b31848859..aa1699c18add8 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 eb62429681fc8..eeea6d54b198c 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 b5fbcd2c17808..5e5ceb5b9631f 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 184ec3c1eae44..05e89d4fa911a 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -243,15 +243,12 @@ 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 f348e564f7dd5..e39bd0ff69f3a 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 185beb2905801..247ef0b9bfa4e 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2111,14 +2111,11 @@ 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; @@ -2137,14 +2134,14 @@ 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 021ed64ee608f..086821b44def1 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 315db3d0229bf..0fcdc0233faca 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -128,16 +128,14 @@ 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 (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); - } + 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 879b8e3f609cd..f54c152bf2bf9 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 350e94d0cac23..e5dd46b1bff8c 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 (!p || p == current || task_is_running(p) || !task_stack_page(p)) + if (!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 aa92cc933889d..45240ec6b85a4 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 717de05c81f49..1c28e3cddb60d 100644 --- a/arch/sh/kernel/process_32.c +++ b/arch/sh/kernel/process_32.c @@ -182,13 +182,10 @@ __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 b6242f7771e9e..647bf0ac7beb9 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 5cf145f18f36b..ae851e8fce4c9 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 93983d6d431de..29a2f396f8601 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; @@ -376,9 +376,6 @@ 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 d33c58a58d4ff..fa8db86e561c7 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; @@ -674,9 +674,6 @@ 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 b5cf0ed116d9e..579692a40a556 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 457a38db368b7..82107373ac7e9 100644 --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -364,14 +364,11 @@ 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 d2c11378c7832..6f9ed2e800f21 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 cd426c3283ee1..266962547b58c 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -943,13 +943,10 @@ 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) { unsigned long entry = 0;
- if (p == current || task_is_running(p)) - return 0; - stack_trace_save_tsk(p, &entry, 1, 0); return entry; } diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index 7f63aca6a0d34..ad15fbc572838 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 0601653406123..47f933fed8700 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -298,15 +298,12 @@ 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 8e10c7accdbcc..4ee118cf06971 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2030,6 +2030,7 @@ 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 9289da7f0ac4a..5ea5b6d8b2a94 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1960,6 +1960,25 @@ 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))