From: "Eric W. Biederman" ebiederm@xmission.com
commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.
There are two big uses of do_exit. The first is it's design use to be the guts of the exit(2) system call. The second use is to terminate a task after something catastrophic has happened like a NULL pointer in kernel code.
Add a function make_task_dead that is initialy exactly the same as do_exit to cover the cases where do_exit is called to handle catastrophic failure. In time this can probably be reduced to just a light wrapper around do_task_dead. For now keep it exactly the same so that there will be no behavioral differences introducing this new concept.
Replace all of the uses of do_exit that use it for catastraphic task cleanup with make_task_dead to make it clear what the code is doing.
As part of this rename rewind_stack_do_exit rewind_stack_and_make_dead.
Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/alpha/kernel/traps.c | 6 +++--- arch/alpha/mm/fault.c | 2 +- arch/arm/kernel/traps.c | 2 +- arch/arm/mm/fault.c | 2 +- arch/arm64/kernel/traps.c | 2 +- arch/arm64/mm/fault.c | 2 +- arch/h8300/kernel/traps.c | 2 +- arch/h8300/mm/fault.c | 2 +- arch/hexagon/kernel/traps.c | 2 +- arch/ia64/kernel/mca_drv.c | 2 +- arch/ia64/kernel/traps.c | 2 +- arch/ia64/mm/fault.c | 2 +- arch/m68k/kernel/traps.c | 2 +- arch/m68k/mm/fault.c | 2 +- arch/microblaze/kernel/exceptions.c | 4 ++-- arch/mips/kernel/traps.c | 2 +- arch/nds32/kernel/traps.c | 8 ++++---- arch/nios2/kernel/traps.c | 4 ++-- arch/openrisc/kernel/traps.c | 2 +- arch/parisc/kernel/traps.c | 2 +- arch/powerpc/kernel/traps.c | 2 +- arch/riscv/kernel/traps.c | 2 +- arch/riscv/mm/fault.c | 2 +- arch/s390/kernel/dumpstack.c | 2 +- arch/s390/kernel/nmi.c | 2 +- arch/sh/kernel/traps.c | 2 +- arch/sparc/kernel/traps_32.c | 4 +--- arch/sparc/kernel/traps_64.c | 4 +--- arch/x86/entry/entry_32.S | 6 +++--- arch/x86/entry/entry_64.S | 6 +++--- arch/x86/kernel/dumpstack.c | 4 ++-- arch/xtensa/kernel/traps.c | 2 +- include/linux/sched/task.h | 1 + kernel/exit.c | 9 +++++++++ tools/objtool/check.c | 3 ++- 35 files changed, 56 insertions(+), 49 deletions(-)
--- a/arch/alpha/kernel/traps.c +++ b/arch/alpha/kernel/traps.c @@ -192,7 +192,7 @@ die_if_kernel(char * str, struct pt_regs local_irq_enable(); while (1); } - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
#ifndef CONFIG_MATHEMU @@ -577,7 +577,7 @@ do_entUna(void * va, unsigned long opcod
printk("Bad unaligned kernel access at %016lx: %p %lx %lu\n", pc, va, opcode, reg); - do_exit(SIGSEGV); + make_task_dead(SIGSEGV);
got_exception: /* Ok, we caught the exception, but we don't want it. Is there @@ -632,7 +632,7 @@ got_exception: local_irq_enable(); while (1); } - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
/* --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -206,7 +206,7 @@ retry: printk(KERN_ALERT "Unable to handle kernel paging request at " "virtual address %016lx\n", address); die_if_kernel("Oops", regs, cause, (unsigned long*)regs - 16); - do_exit(SIGKILL); + make_task_dead(SIGKILL);
/* We ran out of memory, or some other thing happened to us that made us unable to handle the page fault gracefully. */ --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -344,7 +344,7 @@ static void oops_end(unsigned long flags if (panic_on_oops) panic("Fatal exception"); if (signr) - do_exit(signr); + make_task_dead(signr); }
/* --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -149,7 +149,7 @@ __do_kernel_fault(struct mm_struct *mm, show_pte(mm, addr); die("Oops", regs, fsr); bust_spinlocks(0); - do_exit(SIGKILL); + make_task_dead(SIGKILL); }
/* --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -224,7 +224,7 @@ void die(const char *str, struct pt_regs raw_spin_unlock_irqrestore(&die_lock, flags);
if (ret != NOTIFY_STOP) - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
static bool show_unhandled_signals_ratelimited(void) --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -268,7 +268,7 @@ static void die_kernel_fault(const char show_pte(addr); die("Oops", regs, esr); bust_spinlocks(0); - do_exit(SIGKILL); + make_task_dead(SIGKILL); }
static void __do_kernel_fault(unsigned long addr, unsigned int esr, --- a/arch/h8300/kernel/traps.c +++ b/arch/h8300/kernel/traps.c @@ -110,7 +110,7 @@ void die(const char *str, struct pt_regs dump(fp);
spin_unlock_irq(&die_lock); - do_exit(SIGSEGV); + make_dead_task(SIGSEGV); }
static int kstack_depth_to_print = 24; --- a/arch/h8300/mm/fault.c +++ b/arch/h8300/mm/fault.c @@ -52,7 +52,7 @@ asmlinkage int do_page_fault(struct pt_r printk(" at virtual address %08lx\n", address); if (!user_mode(regs)) die("Oops", regs, error_code); - do_exit(SIGKILL); + make_dead_task(SIGKILL);
return 1; } --- a/arch/hexagon/kernel/traps.c +++ b/arch/hexagon/kernel/traps.c @@ -234,7 +234,7 @@ int die(const char *str, struct pt_regs panic("Fatal exception");
oops_exit(); - do_exit(err); + make_dead_task(err); return 0; }
--- a/arch/ia64/kernel/mca_drv.c +++ b/arch/ia64/kernel/mca_drv.c @@ -176,7 +176,7 @@ mca_handler_bh(unsigned long paddr, void spin_unlock(&mca_bh_lock);
/* This process is about to be killed itself */ - do_exit(SIGKILL); + make_task_dead(SIGKILL); }
/** --- a/arch/ia64/kernel/traps.c +++ b/arch/ia64/kernel/traps.c @@ -85,7 +85,7 @@ die (const char *str, struct pt_regs *re if (panic_on_oops) panic("Fatal exception");
- do_exit(SIGSEGV); + make_task_dead(SIGSEGV); return 0; }
--- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -302,7 +302,7 @@ retry: regs = NULL; bust_spinlocks(0); if (regs) - do_exit(SIGKILL); + make_task_dead(SIGKILL); return;
out_of_memory: --- a/arch/m68k/kernel/traps.c +++ b/arch/m68k/kernel/traps.c @@ -1139,7 +1139,7 @@ void die_if_kernel (char *str, struct pt pr_crit("%s: %08x\n", str, nr); show_registers(fp); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
asmlinkage void set_esp0(unsigned long ssp) --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -48,7 +48,7 @@ int send_fault_sig(struct pt_regs *regs) pr_alert("Unable to handle kernel access"); pr_cont(" at virtual address %p\n", addr); die_if_kernel("Oops", regs, 0 /*error_code*/); - do_exit(SIGKILL); + make_task_dead(SIGKILL); }
return 1; --- a/arch/microblaze/kernel/exceptions.c +++ b/arch/microblaze/kernel/exceptions.c @@ -44,10 +44,10 @@ void die(const char *str, struct pt_regs pr_warn("Oops: %s, sig: %ld\n", str, err); show_regs(fp); spin_unlock_irq(&die_lock); - /* do_exit() should take care of panic'ing from an interrupt + /* make_task_dead() should take care of panic'ing from an interrupt * context so we don't handle it here */ - do_exit(err); + make_task_dead(err); }
/* for user application debugging */ --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -412,7 +412,7 @@ void __noreturn die(const char *str, str if (regs && kexec_should_crash(current)) crash_kexec(regs);
- do_exit(sig); + make_task_dead(sig); }
extern struct exception_table_entry __start___dbe_table[]; --- a/arch/nds32/kernel/traps.c +++ b/arch/nds32/kernel/traps.c @@ -183,7 +183,7 @@ void die(const char *str, struct pt_regs
bust_spinlocks(0); spin_unlock_irq(&die_lock); - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
EXPORT_SYMBOL(die); @@ -286,7 +286,7 @@ void unhandled_interruption(struct pt_re pr_emerg("unhandled_interruption\n"); show_regs(regs); if (!user_mode(regs)) - do_exit(SIGKILL); + make_task_dead(SIGKILL); force_sig(SIGKILL, current); }
@@ -297,7 +297,7 @@ void unhandled_exceptions(unsigned long addr, type); show_regs(regs); if (!user_mode(regs)) - do_exit(SIGKILL); + make_task_dead(SIGKILL); force_sig(SIGKILL, current); }
@@ -324,7 +324,7 @@ void do_revinsn(struct pt_regs *regs) pr_emerg("Reserved Instruction\n"); show_regs(regs); if (!user_mode(regs)) - do_exit(SIGILL); + make_task_dead(SIGILL); force_sig(SIGILL, current); }
--- a/arch/nios2/kernel/traps.c +++ b/arch/nios2/kernel/traps.c @@ -37,10 +37,10 @@ void die(const char *str, struct pt_regs show_regs(regs); spin_unlock_irq(&die_lock); /* - * do_exit() should take care of panic'ing from an interrupt + * make_task_dead() should take care of panic'ing from an interrupt * context so we don't handle it here */ - do_exit(err); + make_task_dead(err); }
void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr) --- a/arch/openrisc/kernel/traps.c +++ b/arch/openrisc/kernel/traps.c @@ -224,7 +224,7 @@ void die(const char *str, struct pt_regs __asm__ __volatile__("l.nop 1"); do {} while (1); #endif - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
/* This is normally the 'Oops' routine */ --- a/arch/parisc/kernel/traps.c +++ b/arch/parisc/kernel/traps.c @@ -265,7 +265,7 @@ void die_if_kernel(char *str, struct pt_ panic("Fatal exception");
oops_exit(); - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
/* gdb uses break 4,8 */ --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -251,7 +251,7 @@ static void oops_end(unsigned long flags panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); - do_exit(signr); + make_task_dead(signr); } NOKPROBE_SYMBOL(oops_end);
--- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -64,7 +64,7 @@ void die(struct pt_regs *regs, const cha if (panic_on_oops) panic("Fatal exception"); if (ret != NOTIFY_STOP) - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
void do_trap(struct pt_regs *regs, int signo, int code, --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -200,7 +200,7 @@ no_context: (addr < PAGE_SIZE) ? "NULL pointer dereference" : "paging request", addr); die(regs, "Oops"); - do_exit(SIGKILL); + make_task_dead(SIGKILL);
/* * We ran out of memory, call the OOM killer, and return the userspace --- a/arch/s390/kernel/dumpstack.c +++ b/arch/s390/kernel/dumpstack.c @@ -187,5 +187,5 @@ void die(struct pt_regs *regs, const cha if (panic_on_oops) panic("Fatal exception: panic_on_oops"); oops_exit(); - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); } --- a/arch/s390/kernel/nmi.c +++ b/arch/s390/kernel/nmi.c @@ -179,7 +179,7 @@ void s390_handle_mcck(void) "malfunction (code 0x%016lx).\n", mcck.mcck_code); printk(KERN_EMERG "mcck: task: %s, pid: %d.\n", current->comm, current->pid); - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); } } EXPORT_SYMBOL_GPL(s390_handle_mcck); --- a/arch/sh/kernel/traps.c +++ b/arch/sh/kernel/traps.c @@ -57,7 +57,7 @@ void die(const char *str, struct pt_regs if (panic_on_oops) panic("Fatal exception");
- do_exit(SIGSEGV); + make_task_dead(SIGSEGV); }
void die_if_kernel(const char *str, struct pt_regs *regs, long err) --- a/arch/sparc/kernel/traps_32.c +++ b/arch/sparc/kernel/traps_32.c @@ -86,9 +86,7 @@ void __noreturn die_if_kernel(char *str, } printk("Instruction DUMP:"); instruction_dump ((unsigned long *) regs->pc); - if(regs->psr & PSR_PS) - do_exit(SIGKILL); - do_exit(SIGSEGV); + make_task_dead((regs->psr & PSR_PS) ? SIGKILL : SIGSEGV); }
void do_hw_interrupt(struct pt_regs *regs, unsigned long type) --- a/arch/sparc/kernel/traps_64.c +++ b/arch/sparc/kernel/traps_64.c @@ -2565,9 +2565,7 @@ void __noreturn die_if_kernel(char *str, } if (panic_on_oops) panic("Fatal exception"); - if (regs->tstate & TSTATE_PRIV) - do_exit(SIGKILL); - do_exit(SIGSEGV); + make_task_dead((regs->tstate & TSTATE_PRIV)? SIGKILL : SIGSEGV); } EXPORT_SYMBOL(die_if_kernel);
--- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1500,13 +1500,13 @@ ENTRY(async_page_fault) END(async_page_fault) #endif
-ENTRY(rewind_stack_do_exit) +ENTRY(rewind_stack_and_make_dead) /* Prevent any naive code from trying to unwind to our caller. */ xorl %ebp, %ebp
movl PER_CPU_VAR(cpu_current_top_of_stack), %esi leal -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%esi), %esp
- call do_exit + call make_task_dead 1: jmp 1b -END(rewind_stack_do_exit) +END(rewind_stack_and_make_dead) --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1762,7 +1762,7 @@ ENTRY(ignore_sysret) sysretl END(ignore_sysret)
-ENTRY(rewind_stack_do_exit) +ENTRY(rewind_stack_and_make_dead) UNWIND_HINT_FUNC /* Prevent any naive code from trying to unwind to our caller. */ xorl %ebp, %ebp @@ -1771,5 +1771,5 @@ ENTRY(rewind_stack_do_exit) leaq -PTREGS_SIZE(%rax), %rsp UNWIND_HINT_REGS
- call do_exit -END(rewind_stack_do_exit) + call make_task_dead +END(rewind_stack_and_make_dead) --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -326,7 +326,7 @@ unsigned long oops_begin(void) } NOKPROBE_SYMBOL(oops_begin);
-void __noreturn rewind_stack_do_exit(int signr); +void __noreturn rewind_stack_and_make_dead(int signr);
void oops_end(unsigned long flags, struct pt_regs *regs, int signr) { @@ -361,7 +361,7 @@ void oops_end(unsigned long flags, struc * reuse the task stack and that existing poisons are invalid. */ kasan_unpoison_task_stack(current); - rewind_stack_do_exit(signr); + rewind_stack_and_make_dead(signr); } NOKPROBE_SYMBOL(oops_end);
--- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -542,5 +542,5 @@ void die(const char * str, struct pt_reg if (panic_on_oops) panic("Fatal exception");
- do_exit(err); + make_task_dead(err); } --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -36,6 +36,7 @@ extern int sched_fork(unsigned long clon extern void sched_dead(struct task_struct *p);
void __noreturn do_task_dead(void); +void __noreturn make_task_dead(int signr);
extern void proc_caches_init(void);
--- a/kernel/exit.c +++ b/kernel/exit.c @@ -922,6 +922,15 @@ void __noreturn do_exit(long code) } EXPORT_SYMBOL_GPL(do_exit);
+void __noreturn make_task_dead(int signr) +{ + /* + * Take the task off the cpu after something catastrophic has + * happened. + */ + do_exit(signr); +} + void complete_and_exit(struct completion *comp, long code) { if (comp) --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -159,6 +159,7 @@ static int __dead_end_function(struct ob "panic", "do_exit", "do_task_dead", + "make_task_dead", "__module_put_and_exit", "complete_and_exit", "kvm_spurious_fault", @@ -167,7 +168,7 @@ static int __dead_end_function(struct ob "fortify_panic", "usercopy_abort", "machine_real_restart", - "rewind_stack_do_exit", + "rewind_stack_and_make_dead" };
if (func->bind == STB_WEAK)