508a92741a
This patch fixes a crash caused by an interrupt coming in when an IRQ stack is being torn down. When this happens, handle_signal will loop, setting up the IRQ stack again because the tearing down had finished, and handling whatever signals had come in. However, to_irq_stack returns a mask of pending signals to be handled, plus bit zero is set if the IRQ stack was already active, and thus shouldn't be torn down. This causes a problem because when handle_signal goes around the loop, sig will be zero, and to_irq_stack will duly set bit zero in the returned mask, faking handle_signal into believing that it shouldn't tear down the IRQ stack and return thread_info pointers back to their original values. This will eventually cause a crash, as the IRQ stack thread_info will continue pointing to the original task_struct and an interrupt will look into it after it has been freed. The fix is to stop passing a signal number into to_irq_stack. Rather, the pending signals mask is initialized beforehand with the bit for sig already set. References to sig in to_irq_stack can be replaced with references to the mask. [akpm@linux-foundation.org: use UL] Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
124 lines
4.3 KiB
C
124 lines
4.3 KiB
C
/*
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* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#ifndef __KERN_UTIL_H__
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#define __KERN_UTIL_H__
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#include "sysdep/ptrace.h"
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#include "sysdep/faultinfo.h"
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#include "uml-config.h"
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typedef void (*kern_hndl)(int, union uml_pt_regs *);
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struct kern_handlers {
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kern_hndl relay_signal;
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kern_hndl winch;
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kern_hndl bus_handler;
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kern_hndl page_fault;
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kern_hndl sigio_handler;
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kern_hndl timer_handler;
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};
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extern const struct kern_handlers handlinfo_kern;
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extern int ncpus;
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extern char *gdb_init;
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extern int kmalloc_ok;
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extern int jail;
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extern int nsyscalls;
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#define UML_ROUND_DOWN(addr) ((void *)(((unsigned long) addr) & PAGE_MASK))
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#define UML_ROUND_UP(addr) \
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UML_ROUND_DOWN(((unsigned long) addr) + PAGE_SIZE - 1)
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extern int kernel_fork(unsigned long flags, int (*fn)(void *), void * arg);
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#ifdef UML_CONFIG_MODE_TT
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extern unsigned long stack_sp(unsigned long page);
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#endif
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extern int kernel_thread_proc(void *data);
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extern void syscall_segv(int sig);
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extern int current_pid(void);
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extern unsigned long alloc_stack(int order, int atomic);
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extern int do_signal(void);
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extern int is_stack_fault(unsigned long sp);
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extern unsigned long segv(struct faultinfo fi, unsigned long ip,
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int is_user, union uml_pt_regs *regs);
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extern int handle_page_fault(unsigned long address, unsigned long ip,
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int is_write, int is_user, int *code_out);
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extern void syscall_ready(void);
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extern void set_tracing(void *t, int tracing);
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extern int is_tracing(void *task);
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extern int segv_syscall(void);
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extern void kern_finish_exec(void *task, int new_pid, unsigned long stack);
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extern unsigned long page_mask(void);
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extern int need_finish_fork(void);
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extern void free_stack(unsigned long stack, int order);
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extern void add_input_request(int op, void (*proc)(int), void *arg);
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extern char *current_cmd(void);
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extern void timer_handler(int sig, union uml_pt_regs *regs);
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extern int set_signals(int enable);
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extern int pid_to_processor_id(int pid);
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extern void deliver_signals(void *t);
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extern int next_trap_index(int max);
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extern void default_idle(void);
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extern void finish_fork(void);
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extern void paging_init(void);
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extern void init_flush_vm(void);
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extern void *syscall_sp(void *t);
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extern void syscall_trace(union uml_pt_regs *regs, int entryexit);
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extern int hz(void);
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extern unsigned int do_IRQ(int irq, union uml_pt_regs *regs);
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extern void interrupt_end(void);
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extern void initial_thread_cb(void (*proc)(void *), void *arg);
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extern int debugger_signal(int status, int pid);
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extern void debugger_parent_signal(int status, int pid);
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extern void child_signal(int pid, int status);
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extern int init_ptrace_proxy(int idle_pid, int startup, int stop);
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extern int init_parent_proxy(int pid);
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extern int singlestepping(void *t);
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extern void check_stack_overflow(void *ptr);
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extern void relay_signal(int sig, union uml_pt_regs *regs);
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extern int user_context(unsigned long sp);
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extern void timer_irq(union uml_pt_regs *regs);
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extern void unprotect_stack(unsigned long stack);
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extern void do_uml_exitcalls(void);
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extern int attach_debugger(int idle_pid, int pid, int stop);
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extern int config_gdb(char *str);
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extern int remove_gdb(void);
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extern char *uml_strdup(char *string);
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extern void unprotect_kernel_mem(void);
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extern void protect_kernel_mem(void);
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extern void uml_cleanup(void);
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extern void lock_signalled_task(void *t);
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extern void IPI_handler(int cpu);
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extern int jail_setup(char *line, int *add);
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extern void *get_init_task(void);
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extern int clear_user_proc(void *buf, int size);
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extern int copy_to_user_proc(void *to, void *from, int size);
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extern int copy_from_user_proc(void *to, void *from, int size);
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extern int strlen_user_proc(char *str);
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extern long execute_syscall(void *r);
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extern int smp_sigio_handler(void);
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extern void *get_current(void);
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extern struct task_struct *get_task(int pid, int require);
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extern void machine_halt(void);
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extern int is_syscall(unsigned long addr);
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extern void free_irq(unsigned int, void *);
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extern int cpu(void);
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extern void time_init_kern(void);
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/* Are we disallowed to sleep? Used to choose between GFP_KERNEL and GFP_ATOMIC. */
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extern int __cant_sleep(void);
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extern void sigio_handler(int sig, union uml_pt_regs *regs);
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extern void copy_sc(union uml_pt_regs *regs, void *from);
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extern unsigned long to_irq_stack(unsigned long *mask_out);
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unsigned long from_irq_stack(int nested);
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#endif
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