exit: Add and use make_task_dead.

commit 0e25498f8c 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>
This commit is contained in:
Eric W. Biederman 2023-02-02 16:27:05 -08:00 committed by Greg Kroah-Hartman
parent dd8cccab31
commit 7d5de91a9a
35 changed files with 57 additions and 49 deletions

View File

@ -192,7 +192,7 @@ 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
@ -577,7 +577,7 @@ 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
@ -632,7 +632,7 @@ got_exception:
local_irq_enable();
while (1);
}
do_exit(SIGSEGV);
make_task_dead(SIGSEGV);
}
/*

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@ -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. */

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@ -344,7 +344,7 @@ 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);
}
/*

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@ -149,7 +149,7 @@ __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
show_pte(mm, addr);
die("Oops", regs, fsr);
bust_spinlocks(0);
do_exit(SIGKILL);
make_task_dead(SIGKILL);
}
/*

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@ -224,7 +224,7 @@ 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 bool show_unhandled_signals_ratelimited(void)

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@ -268,7 +268,7 @@ 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);
}
static void __do_kernel_fault(unsigned long addr, unsigned int esr,

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@ -110,7 +110,7 @@ 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;

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@ -52,7 +52,7 @@ 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;
}

View File

@ -234,7 +234,7 @@ 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;
}

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@ -11,6 +11,7 @@
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kallsyms.h>
@ -176,7 +177,7 @@ 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);
}
/**

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@ -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;
}

View File

@ -302,7 +302,7 @@ retry:
regs = NULL;
bust_spinlocks(0);
if (regs)
do_exit(SIGKILL);
make_task_dead(SIGKILL);
return;
out_of_memory:

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@ -1139,7 +1139,7 @@ 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)

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@ -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;

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@ -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 */

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@ -412,7 +412,7 @@ 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[];

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@ -183,7 +183,7 @@ void 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);
@ -286,7 +286,7 @@ 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, current);
}
@ -297,7 +297,7 @@ 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, 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);
}

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@ -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)

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@ -224,7 +224,7 @@ void 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 */

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@ -265,7 +265,7 @@ 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 */

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@ -251,7 +251,7 @@ static void oops_end(unsigned long flags, struct pt_regs *regs,
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception");
do_exit(signr);
make_task_dead(signr);
}
NOKPROBE_SYMBOL(oops_end);

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@ -64,7 +64,7 @@ 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,

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@ -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

View File

@ -187,5 +187,5 @@ void 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);
}

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@ -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);

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@ -57,7 +57,7 @@ void 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)

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@ -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)

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@ -2565,9 +2565,7 @@ 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);

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@ -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)

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@ -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)

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@ -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, 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);

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@ -542,5 +542,5 @@ void die(const char * str, struct pt_regs * regs, long err)
if (panic_on_oops)
panic("Fatal exception");
do_exit(err);
make_task_dead(err);
}

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@ -36,6 +36,7 @@ extern int sched_fork(unsigned long clone_flags, 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);

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@ -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)

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@ -159,6 +159,7 @@ static int __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",
"kvm_spurious_fault",
@ -167,7 +168,7 @@ static int __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"
};
if (func->bind == STB_WEAK)