Commit 0e25498f authored by Eric W. Biederman's avatar Eric W. Biederman

exit: Add and use make_task_dead.

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: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 5e354747
......@@ -190,7 +190,7 @@ die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
local_irq_enable();
while (1);
}
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
#ifndef CONFIG_MATHEMU
......@@ -575,7 +575,7 @@ do_entUna(void * va, unsigned long opcode, unsigned long reg,
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
......@@ -630,7 +630,7 @@ do_entUna(void * va, unsigned long opcode, unsigned long reg,
local_irq_enable();
while (1);
}
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
/*
......
......@@ -204,7 +204,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
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. */
......
......@@ -333,7 +333,7 @@ static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
if (panic_on_oops)
panic("Fatal exception");
if (signr)
do_exit(signr);
make_task_dead(signr);
}
/*
......
......@@ -111,7 +111,7 @@ static void die_kernel_fault(const char *msg, struct mm_struct *mm,
show_pte(KERN_ALERT, mm, addr);
die("Oops", regs, fsr);
bust_spinlocks(0);
do_exit(SIGKILL);
make_task_dead(SIGKILL);
}
/*
......
......@@ -235,7 +235,7 @@ void die(const char *str, struct pt_regs *regs, int err)
raw_spin_unlock_irqrestore(&die_lock, flags);
if (ret != NOTIFY_STOP)
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
static void arm64_show_signal(int signo, const char *str)
......
......@@ -302,7 +302,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
show_pte(addr);
die("Oops", regs, esr);
bust_spinlocks(0);
do_exit(SIGKILL);
make_task_dead(SIGKILL);
}
#ifdef CONFIG_KASAN_HW_TAGS
......
......@@ -294,7 +294,7 @@ void csky_alignment(struct pt_regs *regs)
__func__, opcode, rz, rx, imm, addr);
show_regs(regs);
bust_spinlocks(0);
do_exit(SIGKILL);
make_dead_task(SIGKILL);
}
force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)addr);
......
......@@ -109,7 +109,7 @@ void die(struct pt_regs *regs, const char *str)
if (panic_on_oops)
panic("Fatal exception");
if (ret != NOTIFY_STOP)
do_exit(SIGSEGV);
make_dead_task(SIGSEGV);
}
void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
......
......@@ -67,7 +67,7 @@ static inline void no_context(struct pt_regs *regs, unsigned long addr)
pr_alert("Unable to handle kernel paging request at virtual "
"addr 0x%08lx, pc: 0x%08lx\n", addr, regs->pc);
die(regs, "Oops");
do_exit(SIGKILL);
make_task_dead(SIGKILL);
}
static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_fault_t fault)
......
......@@ -106,7 +106,7 @@ void die(const char *str, struct pt_regs *fp, unsigned long err)
dump(fp);
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
make_dead_task(SIGSEGV);
}
static int kstack_depth_to_print = 24;
......
......@@ -51,7 +51,7 @@ asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
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;
}
......@@ -214,7 +214,7 @@ int die(const char *str, struct pt_regs *regs, long err)
panic("Fatal exception");
oops_exit();
do_exit(err);
make_dead_task(err);
return 0;
}
......
......@@ -176,7 +176,7 @@ mca_handler_bh(unsigned long paddr, void *iip, unsigned long ipsr)
spin_unlock(&mca_bh_lock);
/* This process is about to be killed itself */
do_exit(SIGKILL);
make_task_dead(SIGKILL);
}
/**
......
......@@ -85,7 +85,7 @@ die (const char *str, struct pt_regs *regs, long err)
if (panic_on_oops)
panic("Fatal exception");
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
return 0;
}
......
......@@ -259,7 +259,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
regs = NULL;
bust_spinlocks(0);
if (regs)
do_exit(SIGKILL);
make_task_dead(SIGKILL);
return;
out_of_memory:
......
......@@ -1131,7 +1131,7 @@ void die_if_kernel (char *str, struct pt_regs *fp, int nr)
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)
......
......@@ -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;
......
......@@ -44,10 +44,10 @@ void die(const char *str, struct pt_regs *fp, long err)
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 */
......
......@@ -422,7 +422,7 @@ void __noreturn die(const char *str, struct pt_regs *regs)
if (regs && kexec_should_crash(current))
crash_kexec(regs);
do_exit(sig);
make_task_dead(sig);
}
extern struct exception_table_entry __start___dbe_table[];
......
......@@ -223,7 +223,7 @@ inline void handle_fpu_exception(struct pt_regs *regs)
}
} else if (fpcsr & FPCSR_mskRIT) {
if (!user_mode(regs))
do_exit(SIGILL);
make_task_dead(SIGILL);
si_signo = SIGILL;
}
......
......@@ -141,7 +141,7 @@ void __noreturn die(const char *str, struct pt_regs *regs, int err)
bust_spinlocks(0);
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
EXPORT_SYMBOL(die);
......@@ -240,7 +240,7 @@ void unhandled_interruption(struct pt_regs *regs)
pr_emerg("unhandled_interruption\n");
show_regs(regs);
if (!user_mode(regs))
do_exit(SIGKILL);
make_task_dead(SIGKILL);
force_sig(SIGKILL);
}
......@@ -251,7 +251,7 @@ void unhandled_exceptions(unsigned long entry, unsigned long addr,
addr, type);
show_regs(regs);
if (!user_mode(regs))
do_exit(SIGKILL);
make_task_dead(SIGKILL);
force_sig(SIGKILL);
}
......@@ -278,7 +278,7 @@ 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);
}
......
......@@ -37,10 +37,10 @@ void die(const char *str, struct pt_regs *regs, long err)
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)
......
......@@ -212,7 +212,7 @@ void __noreturn die(const char *str, struct pt_regs *regs, long err)
__asm__ __volatile__("l.nop 1");
do {} while (1);
#endif
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
/* This is normally the 'Oops' routine */
......
......@@ -269,7 +269,7 @@ void die_if_kernel(char *str, struct pt_regs *regs, long err)
panic("Fatal exception");
oops_exit();
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
/* gdb uses break 4,8 */
......
......@@ -245,7 +245,7 @@ static void oops_end(unsigned long flags, struct pt_regs *regs,
if (panic_on_oops)
panic("Fatal exception");
do_exit(signr);
make_task_dead(signr);
}
NOKPROBE_SYMBOL(oops_end);
......@@ -792,9 +792,9 @@ int machine_check_generic(struct pt_regs *regs)
void die_mce(const char *str, struct pt_regs *regs, long err)
{
/*
* The machine check wants to kill the interrupted context, but
* do_exit() checks for in_interrupt() and panics in that case, so
* exit the irq/nmi before calling die.
* The machine check wants to kill the interrupted context,
* but make_task_dead() checks for in_interrupt() and panics
* in that case, so exit the irq/nmi before calling die.
*/
if (in_nmi())
nmi_exit();
......
......@@ -54,7 +54,7 @@ void die(struct pt_regs *regs, const char *str)
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, unsigned long addr)
......
......@@ -31,7 +31,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
bust_spinlocks(0);
die(regs, "Oops");
do_exit(SIGKILL);
make_task_dead(SIGKILL);
}
static inline void no_context(struct pt_regs *regs, unsigned long addr)
......
......@@ -224,5 +224,5 @@ void __noreturn die(struct pt_regs *regs, const char *str)
if (panic_on_oops)
panic("Fatal exception: panic_on_oops");
oops_exit();
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
......@@ -175,7 +175,7 @@ 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);
}
}
......
......@@ -57,7 +57,7 @@ void __noreturn die(const char *str, struct pt_regs *regs, long err)
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)
......
......@@ -86,9 +86,7 @@ void __noreturn die_if_kernel(char *str, struct pt_regs *regs)
}
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)
......
......@@ -2559,9 +2559,7 @@ void __noreturn die_if_kernel(char *str, struct pt_regs *regs)
}
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);
......
......@@ -1248,14 +1248,14 @@ SYM_CODE_START(asm_exc_nmi)
SYM_CODE_END(asm_exc_nmi)
.pushsection .text, "ax"
SYM_CODE_START(rewind_stack_do_exit)
SYM_CODE_START(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
SYM_CODE_END(rewind_stack_do_exit)
SYM_CODE_END(rewind_stack_and_make_dead)
.popsection
......@@ -1429,7 +1429,7 @@ SYM_CODE_END(ignore_sysret)
#endif
.pushsection .text, "ax"
SYM_CODE_START(rewind_stack_do_exit)
SYM_CODE_START(rewind_stack_and_make_dead)
UNWIND_HINT_FUNC
/* Prevent any naive code from trying to unwind to our caller. */
xorl %ebp, %ebp
......@@ -1438,6 +1438,6 @@ SYM_CODE_START(rewind_stack_do_exit)
leaq -PTREGS_SIZE(%rax), %rsp
UNWIND_HINT_REGS
call do_exit
SYM_CODE_END(rewind_stack_do_exit)
call make_task_dead
SYM_CODE_END(rewind_stack_and_make_dead)
.popsection
......@@ -351,7 +351,7 @@ 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)
{
......@@ -386,7 +386,7 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
* 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);
......
......@@ -552,5 +552,5 @@ void __noreturn die(const char * str, struct pt_regs * regs, long err)
if (panic_on_oops)
panic("Fatal exception");
do_exit(err);
make_task_dead(err);
}
......@@ -59,6 +59,7 @@ extern void sched_post_fork(struct task_struct *p,
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);
......
......@@ -884,6 +884,15 @@ 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)
......
......@@ -168,6 +168,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
"panic",
"do_exit",
"do_task_dead",
"make_task_dead",
"__module_put_and_exit",
"complete_and_exit",
"__reiserfs_panic",
......@@ -175,7 +176,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
"fortify_panic",
"usercopy_abort",
"machine_real_restart",
"rewind_stack_do_exit",
"rewind_stack_and_make_dead"
"kunit_try_catch_throw",
"xen_start_kernel",
"cpu_bringup_and_idle",
......
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