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Re: [patch] thread-aware coredumps, 2.5.43-C3



This patch is working pretty well for me with only one problem, which seems 
to have happened indepently of Ingo's patch.

Extended floating point note sections are no longer getting recognized by GDB 
5.x.  

After a bit of poking around in the GDB 5.2.1 code (line 6399 bfd/efl.c) I 
noticed that there is a n_namesz test for the reg-xfp section parsing.

The following minor tweak on top of Ingo's patch  to binfmt_elf.c fixes the 
problem.

diff -urN -X dontdiff linux-2.5.43/fs/binfmt_elf.c 
linux-2.5.43.xfp/fs/binfmt_elf.c
--- linux-2.5.43/fs/binfmt_elf.c	Thu Oct 17 16:54:13 2002
+++ linux-2.5.43.xfp/fs/binfmt_elf.c	Thu Oct 17 16:53:00 2002
@@ -964,7 +964,9 @@
 {
 	struct elf_note en;
 
-	en.n_namesz = strlen(men->name) + 1;
+	en.n_namesz = strlen(men->name); 
+	/* en.n_namesz = strlen(men->name) + 1;  gdb checks namez and the + 1 */
+					/*breaks xfp core file note sections. */
 	en.n_descsz = men->datasz;
 	en.n_type = men->type;
 


I don't know when this +1 was added to writenote binfmt_elf.c or why.  I do 
know that newer than July and it isn't in 2.4

If there the + 1 is needed of others then we may need to special case the 
NT_PRXFPREG note sections.

--mgross

On Thursday 17 October 2002 05:11 am, Ingo Molnar wrote:
> the attached patch is the second iteration of thread-aware coredumps,
> against BK-curr. I think this patch is now ready for inclusion into
> mainline.
>
> Changes:
>
> - Ulrich Drepper has reviewed the data structures and checked actual
>   coredumps via readelf - everything looks fine and according to the spec.
>
> - a serious bug has been fixed in the thread-state dumping code - it was
>   still based on the 2.4 assumption that the task struct points to the
>   kernel stack - it's task->thread_info in 2.5. This bug caused bogus
>   register info to be filled in for threads.
>
> - properly wait for all threads that share the same MM to serialize with
>   the coredumping thread. This is CLONE_VM based, not tied to
>   CLONE_THREAD and/or signal semantics, ie. old-style (or different-style)
>   threaded apps will be properly stopped as well.
>
>   The locking might look a bit complex, but i wanted to keep the
>   __exit_mm() overhead as low as possible. It's not quite trivial to get
>   these bits right, because 'sharing the MM' is detached from signals
>   semantics, so we cannot rely on broadcast-kill catching all threads. So
>   zap_threads() iterates through every thread and zaps those which were
>   left out. (There's a minimal race left in where a newly forked child
>   might escape the attention of zap_threads() - this race is fixed by the
>   OOM fixes in the mmap-speedup patch.)
>
> - fill_psinfo() is now called with the thread group leader, for the
>   coredump to get 'process' state.
>
>  - initialize the elf_thread_status structure with zeroes.
>
> the IA64 ELF bits are not included, yet, to reduce complexity of the
> patch. The patch has been tested on x86 UP and SMP.
>
> 	Ingo
>
> --- linux/arch/i386/kernel/i387.c.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/arch/i386/kernel/i387.c	2002-10-17 09:48:55.000000000 +0200
> @@ -528,3 +528,40 @@
>
>  	return fpvalid;
>  }
> +
> +int dump_task_fpu(struct task_struct *tsk, struct user_i387_struct *fpu)
> +{
> +	int fpvalid = tsk->used_math;
> +
> +	if (fpvalid) {
> +		if (tsk == current)
> +			unlazy_fpu(tsk);
> +		if (cpu_has_fxsr)
> +			copy_fpu_fxsave(tsk, fpu);
> +		else
> +			copy_fpu_fsave(tsk, fpu);
> +	}
> +	return fpvalid;
> +}
> +
> +int dump_task_extended_fpu(struct task_struct *tsk, struct
> user_fxsr_struct *fpu) +{
> +	int fpvalid = tsk->used_math && cpu_has_fxsr;
> +
> +	if (fpvalid) {
> +		if (tsk == current)
> +		       unlazy_fpu(tsk);
> +		memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(*fpu));
> +	}
> +	return fpvalid;
> +}
> +
> +
> +#ifdef CONFIG_SMP
> +void dump_smp_unlazy_fpu(void)
> +{
> +	unlazy_fpu(current);
> +	return;
> +}
> +#endif
> +
> --- linux/arch/i386/kernel/process.c.orig	2002-10-17 09:48:47.000000000
> +0200 +++ linux/arch/i386/kernel/process.c	2002-10-17 10:17:22.000000000
> +0200 @@ -19,6 +19,7 @@
>  #include <linux/fs.h>
>  #include <linux/kernel.h>
>  #include <linux/mm.h>
> +#include <linux/elfcore.h>
>  #include <linux/smp.h>
>  #include <linux/smp_lock.h>
>  #include <linux/stddef.h>
> @@ -373,6 +374,25 @@
>  	dump->u_fpvalid = dump_fpu (regs, &dump->i387);
>  }
>
> +/*
> + * Capture the user space registers if the task is not running (in user
> space) + */
> +int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
> +{
> +	struct pt_regs ptregs;
> +
> +	ptregs = *(struct pt_regs *)
> +		((unsigned long)tsk->thread_info+THREAD_SIZE - sizeof(ptregs));
> +	ptregs.xcs &= 0xffff;
> +	ptregs.xds &= 0xffff;
> +	ptregs.xes &= 0xffff;
> +	ptregs.xss &= 0xffff;
> +
> +	elf_core_copy_regs(regs, &ptregs);
> +
> +	return 1;
> +}
> +
>  /*
>   * This special macro can be used to load a debugging register
>   */
> --- linux/arch/ia64/kernel/process.c.orig	2002-10-17 09:48:47.000000000
> +0200 +++ linux/arch/ia64/kernel/process.c	2002-10-17 09:48:55.000000000
> +0200 @@ -382,6 +382,31 @@
>  void
>  do_copy_regs (struct unw_frame_info *info, void *arg)
>  {
> +	do_copy_task_regs(current, info, arg);
> +}
> +
> +void
> +do_dump_fpu (struct unw_frame_info *info, void *arg)
> +{
> +	do_dump_task_fpu(current, info, arg);
> +}
> +
> +void
> +ia64_elf_core_copy_regs (struct pt_regs *pt, elf_gregset_t dst)
> +{
> +	unw_init_running(do_copy_regs, dst);
> +}
> +
> +int
> +dump_fpu (struct pt_regs *pt, elf_fpregset_t dst)
> +{
> +	unw_init_running(do_dump_fpu, dst);
> +	return 1;	/* f0-f31 are always valid so we always return 1 */
> +}
> +
> +static void
> +do_copy_task_regs (struct task_struct *task, struct unw_frame_info *info,
> void *arg) +{
>  	unsigned long mask, sp, nat_bits = 0, ip, ar_rnat, urbs_end, cfm;
>  	elf_greg_t *dst = arg;
>  	struct pt_regs *pt;
> @@ -396,12 +421,12 @@
>  	unw_get_sp(info, &sp);
>  	pt = (struct pt_regs *) (sp + 16);
>
> -	urbs_end = ia64_get_user_rbs_end(current, pt, &cfm);
> +	urbs_end = ia64_get_user_rbs_end(task, pt, &cfm);
>
> -	if (ia64_sync_user_rbs(current, info->sw, pt->ar_bspstore, urbs_end) < 0)
> +	if (ia64_sync_user_rbs(task, info->sw, pt->ar_bspstore, urbs_end) < 0)
>  		return;
>
> -	ia64_peek(current, info->sw, urbs_end, (long) ia64_rse_rnat_addr((long *)
> urbs_end), +	ia64_peek(task, info->sw, urbs_end, (long)
> ia64_rse_rnat_addr((long *) urbs_end), &ar_rnat);
>
>  	/*
> @@ -450,7 +475,7 @@
>  }
>
>  void
> -do_dump_fpu (struct unw_frame_info *info, void *arg)
> +do_dump_task_fpu (struct task_struct *task, struct unw_frame_info *info,
> void *arg) {
>  	elf_fpreg_t *dst = arg;
>  	int i;
> @@ -465,22 +490,41 @@
>  	for (i = 2; i < 32; ++i)
>  		unw_get_fr(info, i, dst + i);
>
> -	ia64_flush_fph(current);
> -	if ((current->thread.flags & IA64_THREAD_FPH_VALID) != 0)
> -		memcpy(dst + 32, current->thread.fph, 96*16);
> +	ia64_flush_fph(task);
> +	if ((task->thread.flags & IA64_THREAD_FPH_VALID) != 0)
> +		memcpy(dst + 32, task->thread.fph, 96*16);
>  }
>
> -void
> -ia64_elf_core_copy_regs (struct pt_regs *pt, elf_gregset_t dst)
> +int dump_task_regs(struct task_struct *task, elf_gregset_t *regs)
>  {
> -	unw_init_running(do_copy_regs, dst);
> +	struct unw_frame_info tcore_info;
> +
> +	if(current == task) {
> +		unw_init_running(do_copy_regs, regs);
> +	}
> +	else {
> +		memset(&tcore_info, 0, sizeof(tcore_info));
> +		unw_init_from_blocked_task(&tcore_info, task);
> +		do_copy_task_regs(task, &tcore_info, regs);
> +	}
> +
> +	return 1;
>  }
>
> -int
> -dump_fpu (struct pt_regs *pt, elf_fpregset_t dst)
> +int dump_task_fpu (struct task_struct *task, elf_fpregset_t *dst)
>  {
> -	unw_init_running(do_dump_fpu, dst);
> -	return 1;	/* f0-f31 are always valid so we always return 1 */
> +	struct unw_frame_info tcore_info;
> +
> +	if(current == task) {
> +		unw_init_running(do_dump_fpu, dst);
> +	}
> +	else {
> +		memset(&tcore_info, 0, sizeof(tcore_info));
> +		unw_init_from_blocked_task(&tcore_info, task);
> +		do_dump_task_fpu(task, &tcore_info, dst);
> +	}
> +
> +	return 1;
>  }
>
>  asmlinkage long
> --- linux/fs/binfmt_elf.c.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/fs/binfmt_elf.c	2002-10-17 10:56:25.000000000 +0200
> @@ -30,6 +30,7 @@
>  #include <linux/elfcore.h>
>  #include <linux/init.h>
>  #include <linux/highuid.h>
> +#include <linux/smp.h>
>  #include <linux/smp_lock.h>
>  #include <linux/compiler.h>
>  #include <linux/highmem.h>
> @@ -534,9 +535,6 @@
>  			if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 ||
>  			    strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0)
>  				ibcs2_interpreter = 1;
> -#if 0
> -			printk("Using ELF interpreter %s\n", elf_interpreter);
> -#endif
>
>  			SET_PERSONALITY(elf_ex, ibcs2_interpreter);
>
> @@ -759,16 +757,6 @@
>
>  	padzero(elf_bss);
>
> -#if 0
> -	printk("(start_brk) %lx\n" , (long) current->mm->start_brk);
> -	printk("(end_code) %lx\n" , (long) current->mm->end_code);
> -	printk("(start_code) %lx\n" , (long) current->mm->start_code);
> -	printk("(start_data) %lx\n" , (long) current->mm->start_data);
> -	printk("(end_data) %lx\n" , (long) current->mm->end_data);
> -	printk("(start_stack) %lx\n" , (long) current->mm->start_stack);
> -	printk("(brk) %lx\n" , (long) current->mm->brk);
> -#endif
> -
>  	if (current->personality & MMAP_PAGE_ZERO) {
>  		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
>  		   and some applications "depend" upon this behavior.
> @@ -967,26 +955,6 @@
>  	return sz;
>  }
>
> -/* #define DEBUG */
> -
> -#ifdef DEBUG
> -static void dump_regs(const char *str, elf_greg_t *r)
> -{
> -	int i;
> -	static const char *regs[] = { "ebx", "ecx", "edx", "esi", "edi", "ebp",
> -					      "eax", "ds", "es", "fs", "gs",
> -					      "orig_eax", "eip", "cs",
> -					      "efl", "uesp", "ss"};
> -	printk("Registers: %s\n", str);
> -
> -	for(i = 0; i < ELF_NGREG; i++)
> -	{
> -		unsigned long val = r[i];
> -		printk("   %-2d %-5s=%08lx %lu\n", i, regs[i], val, val);
> -	}
> -}
> -#endif
> -
>  #define DUMP_WRITE(addr, nr)	\
>  	do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
>  #define DUMP_SEEK(off)	\
> @@ -1018,6 +986,164 @@
>  #define DUMP_SEEK(off)	\
>  	if (!dump_seek(file, (off))) \
>  		goto end_coredump;
> +
> +static inline void fill_elf_header(struct elfhdr *elf, int segs)
> +{
> +	memcpy(elf->e_ident, ELFMAG, SELFMAG);
> +	elf->e_ident[EI_CLASS] = ELF_CLASS;
> +	elf->e_ident[EI_DATA] = ELF_DATA;
> +	elf->e_ident[EI_VERSION] = EV_CURRENT;
> +	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
> +
> +	elf->e_type = ET_CORE;
> +	elf->e_machine = ELF_ARCH;
> +	elf->e_version = EV_CURRENT;
> +	elf->e_entry = 0;
> +	elf->e_phoff = sizeof(struct elfhdr);
> +	elf->e_shoff = 0;
> +	elf->e_flags = 0;
> +	elf->e_ehsize = sizeof(struct elfhdr);
> +	elf->e_phentsize = sizeof(struct elf_phdr);
> +	elf->e_phnum = segs;
> +	elf->e_shentsize = 0;
> +	elf->e_shnum = 0;
> +	elf->e_shstrndx = 0;
> +	return;
> +}
> +
> +static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, off_t
> offset) +{
> +	phdr->p_type = PT_NOTE;
> +	phdr->p_offset = offset;
> +	phdr->p_vaddr = 0;
> +	phdr->p_paddr = 0;
> +	phdr->p_filesz = sz;
> +	phdr->p_memsz = 0;
> +	phdr->p_flags = 0;
> +	phdr->p_align = 0;
> +	return;
> +}
> +
> +static inline void fill_note(struct memelfnote *note, const char *name,
> int type, +		unsigned int sz, void *data)
> +{
> +	note->name = name;
> +	note->type = type;
> +	note->datasz = sz;
> +	note->data = data;
> +	return;
> +}
> +
> +/*
> + * fill up all the fields in prstatus from the given task struct, except
> registers + * which need to be filled up seperately.
> + */
> +static inline void fill_prstatus(struct elf_prstatus *prstatus, struct
> task_struct *p, long signr) +{
> +	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
> +	prstatus->pr_sigpend = p->pending.signal.sig[0];
> +	prstatus->pr_sighold = p->blocked.sig[0];
> +	prstatus->pr_pid = p->pid;
> +	prstatus->pr_ppid = p->parent->pid;
> +	prstatus->pr_pgrp = p->pgrp;
> +	prstatus->pr_sid = p->session;
> +	jiffies_to_timeval(p->utime, &prstatus->pr_utime);
> +	jiffies_to_timeval(p->stime, &prstatus->pr_stime);
> +	jiffies_to_timeval(p->cutime, &prstatus->pr_cutime);
> +	jiffies_to_timeval(p->cstime, &prstatus->pr_cstime);
> +}
> +
> +static inline void fill_psinfo(struct elf_prpsinfo *psinfo, struct
> task_struct *p) +{
> +	int i, len;
> +
> +	/* first copy the parameters from user space */
> +	memset(psinfo, 0, sizeof(struct elf_prpsinfo));
> +
> +	len = p->mm->arg_end - p->mm->arg_start;
> +	if (len >= ELF_PRARGSZ)
> +		len = ELF_PRARGSZ-1;
> +	copy_from_user(&psinfo->pr_psargs,
> +		      (const char *)p->mm->arg_start, len);
> +	for(i = 0; i < len; i++)
> +		if (psinfo->pr_psargs[i] == 0)
> +			psinfo->pr_psargs[i] = ' ';
> +	psinfo->pr_psargs[len] = 0;
> +
> +	psinfo->pr_pid = p->pid;
> +	psinfo->pr_ppid = p->parent->pid;
> +	psinfo->pr_pgrp = p->pgrp;
> +	psinfo->pr_sid = p->session;
> +
> +	i = p->state ? ffz(~p->state) + 1 : 0;
> +	psinfo->pr_state = i;
> +	psinfo->pr_sname = (i < 0 || i > 5) ? '.' : "RSDZTD"[i];
> +	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
> +	psinfo->pr_nice = task_nice(p);
> +	psinfo->pr_flag = p->flags;
> +	psinfo->pr_uid = NEW_TO_OLD_UID(p->uid);
> +	psinfo->pr_gid = NEW_TO_OLD_GID(p->gid);
> +	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
> +
> +	return;
> +}
> +
> +/* Here is the structure in which status of each thread is captured. */
> +struct elf_thread_status
> +{
> +	struct list_head list;
> +	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
> +	elf_fpregset_t fpu;		/* NT_PRFPREG */
> +#ifdef ELF_CORE_COPY_XFPREGS
> +	elf_fpxregset_t xfpu;		/* NT_PRXFPREG */
> +#endif
> +	struct memelfnote notes[3];
> +	int num_notes;
> +};
> +
> +/*
> + * In order to add the specific thread information for the elf file
> format, + * we need to keep a linked list of every threads pr_status and
> then + * create a single section for them in the final core file.
> + */
> +static int elf_dump_thread_status(long signr, struct task_struct * p,
> struct list_head * thread_list) +{
> +
> +	struct elf_thread_status *t;
> +	int sz = 0;
> +
> +	t = kmalloc(sizeof(*t), GFP_ATOMIC);
> +	if (!t)
> +		return 0;
> +	memset(t, 0, sizeof(*t));
> +
> +	INIT_LIST_HEAD(&t->list);
> +	t->num_notes = 0;
> +
> +	fill_prstatus(&t->prstatus, p, signr);
> +	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
> +
> +	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
> &(t->prstatus)); +	t->num_notes++;
> +	sz += notesize(&t->notes[0]);
> +
> +	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, &t->fpu))) {
> +		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu), &(t->fpu));
> +		t->num_notes++;
> +		sz += notesize(&t->notes[1]);
> +	}
> +
> +#ifdef ELF_CORE_COPY_XFPREGS
> +	if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
> +		fill_note(&t->notes[2], "LINUX", NT_PRXFPREG, sizeof(t->xfpu),
> &t->xfpu); +		t->num_notes++;
> +		sz += notesize(&t->notes[2]);
> +	}
> +#endif
> +	list_add(&t->list, thread_list);
> +	return sz;
> +}
> +
>  /*
>   * Actual dumper
>   *
> @@ -1036,74 +1162,56 @@
>  	struct elfhdr elf;
>  	off_t offset = 0, dataoff;
>  	unsigned long limit = current->rlim[RLIMIT_CORE].rlim_cur;
> -	int numnote = 4;
> -	struct memelfnote notes[4];
> +	int numnote = 5;
> +	struct memelfnote notes[5];
>  	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
> -	elf_fpregset_t fpu;		/* NT_PRFPREG */
>  	struct elf_prpsinfo psinfo;	/* NT_PRPSINFO */
> -
> -	/* first copy the parameters from user space */
> -	memset(&psinfo, 0, sizeof(psinfo));
> -	{
> -		int i, len;
> -
> -		len = current->mm->arg_end - current->mm->arg_start;
> -		if (len >= ELF_PRARGSZ)
> -			len = ELF_PRARGSZ-1;
> -		copy_from_user(&psinfo.pr_psargs,
> -			      (const char *)current->mm->arg_start, len);
> -		for(i = 0; i < len; i++)
> -			if (psinfo.pr_psargs[i] == 0)
> -				psinfo.pr_psargs[i] = ' ';
> -		psinfo.pr_psargs[len] = 0;
> -
> -	}
> -
> -	memset(&prstatus, 0, sizeof(prstatus));
> -	/*
> -	 * This transfers the registers from regs into the standard
> -	 * coredump arrangement, whatever that is.
> + 	struct task_struct *g, *p;
> + 	LIST_HEAD(thread_list);
> + 	struct list_head *t;
> +	elf_fpregset_t fpu;
> +#ifdef ELF_CORE_COPY_XFPREGS
> +	elf_fpxregset_t xfpu;
> +#endif
> +	int thread_status_size = 0;
> +
> +	/* We no longer stop all vm operations
> +	 *
> +	 * This because those proceses that could possibly
> +	 * change map_count or the mmap / vma pages are now blocked in do_exit on
> current finishing +	 * this core dump.
> +	 *
> +	 * Only ptrace can touch these memory addresses, but it doesn't change
> +	 * the map_count or the pages allocated.  So no possibility of crashing
> exists while dumping +	 * the mm->vm_next areas to the core file.
> +	 *
>  	 */
> -#ifdef ELF_CORE_COPY_REGS
> -	ELF_CORE_COPY_REGS(prstatus.pr_reg, regs)
> -#else
> -	if (sizeof(elf_gregset_t) != sizeof(struct pt_regs))
> -	{
> -		printk("sizeof(elf_gregset_t) (%ld) != sizeof(struct pt_regs) (%ld)\n",
> -			(long)sizeof(elf_gregset_t), (long)sizeof(struct pt_regs));
> +
> +	 /* capture the status of all other threads */
> +	if (signr) {
> +		read_lock(&tasklist_lock);
> +		do_each_thread(g,p)
> +			if (current->mm == p->mm && current != p) {
> +				int sz = elf_dump_thread_status(signr, p, &thread_list);
> +				if (!sz) {
> +					read_unlock(&tasklist_lock);
> +					goto cleanup;
> +				} else
> +					thread_status_size += sz;
> +			}
> +		while_each_thread(g,p);
> +		read_unlock(&tasklist_lock);
>  	}
> -	else
> -		*(struct pt_regs *)&prstatus.pr_reg = *regs;
> -#endif
>
> -	/* now stop all vm operations */
> -	down_write(&current->mm->mmap_sem);
> +	/* now collect the dump for the current */
> +	memset(&prstatus, 0, sizeof(prstatus));
> +	fill_prstatus(&prstatus, current, signr);
> +	elf_core_copy_regs(&prstatus.pr_reg, regs);
> +
>  	segs = current->mm->map_count;
>
> -#ifdef DEBUG
> -	printk("elf_core_dump: %d segs %lu limit\n", segs, limit);
> -#endif
> -
>  	/* Set up header */
> -	memcpy(elf.e_ident, ELFMAG, SELFMAG);
> -	elf.e_ident[EI_CLASS] = ELF_CLASS;
> -	elf.e_ident[EI_DATA] = ELF_DATA;
> -	elf.e_ident[EI_VERSION] = EV_CURRENT;
> -	memset(elf.e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
> -
> -	elf.e_type = ET_CORE;
> -	elf.e_machine = ELF_ARCH;
> -	elf.e_version = EV_CURRENT;
> -	elf.e_entry = 0;
> -	elf.e_phoff = sizeof(elf);
> -	elf.e_shoff = 0;
> -	elf.e_flags = 0;
> -	elf.e_ehsize = sizeof(elf);
> -	elf.e_phentsize = sizeof(struct elf_phdr);
> -	elf.e_phnum = segs+1;		/* Include notes */
> -	elf.e_shentsize = 0;
> -	elf.e_shnum = 0;
> -	elf.e_shstrndx = 0;
> +	fill_elf_header(&elf, segs+1); /* including notes section*/
>
>  	fs = get_fs();
>  	set_fs(KERNEL_DS);
> @@ -1120,60 +1228,27 @@
>  	 * with info from their /proc.
>  	 */
>
> -	notes[0].name = "CORE";
> -	notes[0].type = NT_PRSTATUS;
> -	notes[0].datasz = sizeof(prstatus);
> -	notes[0].data = &prstatus;
> -	prstatus.pr_info.si_signo = prstatus.pr_cursig = signr;
> -	prstatus.pr_sigpend = current->pending.signal.sig[0];
> -	prstatus.pr_sighold = current->blocked.sig[0];
> -	psinfo.pr_pid = prstatus.pr_pid = current->pid;
> -	psinfo.pr_ppid = prstatus.pr_ppid = current->parent->pid;
> -	psinfo.pr_pgrp = prstatus.pr_pgrp = current->pgrp;
> -	psinfo.pr_sid = prstatus.pr_sid = current->session;
> -	jiffies_to_timeval(current->utime, &prstatus.pr_utime);
> -	jiffies_to_timeval(current->stime, &prstatus.pr_stime);
> -	jiffies_to_timeval(current->cutime, &prstatus.pr_cutime);
> -	jiffies_to_timeval(current->cstime, &prstatus.pr_cstime);
> -
> -#ifdef DEBUG
> -	dump_regs("Passed in regs", (elf_greg_t *)regs);
> -	dump_regs("prstatus regs", (elf_greg_t *)&prstatus.pr_reg);
> -#endif
> -
> -	notes[1].name = "CORE";
> -	notes[1].type = NT_PRPSINFO;
> -	notes[1].datasz = sizeof(psinfo);
> -	notes[1].data = &psinfo;
> -	i = current->state ? ffz(~current->state) + 1 : 0;
> -	psinfo.pr_state = i;
> -	psinfo.pr_sname = (i < 0 || i > 5) ? '.' : "RSDZTD"[i];
> -	psinfo.pr_zomb = psinfo.pr_sname == 'Z';
> -	psinfo.pr_nice = task_nice(current);
> -	psinfo.pr_flag = current->flags;
> -	psinfo.pr_uid = NEW_TO_OLD_UID(current->uid);
> -	psinfo.pr_gid = NEW_TO_OLD_GID(current->gid);
> -	strncpy(psinfo.pr_fname, current->comm, sizeof(psinfo.pr_fname));
> -
> -	notes[2].name = "CORE";
> -	notes[2].type = NT_TASKSTRUCT;
> -	notes[2].datasz = sizeof(*current);
> -	notes[2].data = current;
> -
> -	/* Try to dump the FPU. */
> -	prstatus.pr_fpvalid = dump_fpu (regs, &fpu);
> -	if (!prstatus.pr_fpvalid)
> -	{
> -		numnote--;
> -	}
> -	else
> -	{
> -		notes[3].name = "CORE";
> -		notes[3].type = NT_PRFPREG;
> -		notes[3].datasz = sizeof(fpu);
> -		notes[3].data = &fpu;
> -	}
> +	fill_note(&notes[0], "CORE", NT_PRSTATUS, sizeof(prstatus), &prstatus);
> +
> +	fill_psinfo(&psinfo, current->group_leader);
> +	fill_note(&notes[1], "CORE", NT_PRPSINFO, sizeof(psinfo), &psinfo);
>
> +	fill_note(&notes[2], "CORE", NT_TASKSTRUCT, sizeof(*current), current);
> +
> +  	/* Try to dump the FPU. */
> +	if ((prstatus.pr_fpvalid = elf_core_copy_task_fpregs(current, &fpu)))
> +		fill_note(&notes[3], "CORE", NT_PRFPREG, sizeof(fpu), &fpu);
> +	else
> +		--numnote;
> +#ifdef ELF_CORE_COPY_XFPREGS
> +	if (elf_core_copy_task_xfpregs(current, &xfpu))
> +		fill_note(&notes[4], "LINUX", NT_PRXFPREG, sizeof(xfpu), &xfpu);
> +	else
> +		--numnote;
> +#else
> +	numnote --;
> +#endif
> +
>  	/* Write notes phdr entry */
>  	{
>  		struct elf_phdr phdr;
> @@ -1181,17 +1256,11 @@
>
>  		for(i = 0; i < numnote; i++)
>  			sz += notesize(&notes[i]);
> +
> +		sz += thread_status_size;
>
> -		phdr.p_type = PT_NOTE;
> -		phdr.p_offset = offset;
> -		phdr.p_vaddr = 0;
> -		phdr.p_paddr = 0;
> -		phdr.p_filesz = sz;
> -		phdr.p_memsz = 0;
> -		phdr.p_flags = 0;
> -		phdr.p_align = 0;
> -
> -		offset += phdr.p_filesz;
> +		fill_elf_note_phdr(&phdr, sz, offset);
> +		offset += sz;
>  		DUMP_WRITE(&phdr, sizeof(phdr));
>  	}
>
> @@ -1220,10 +1289,19 @@
>  		DUMP_WRITE(&phdr, sizeof(phdr));
>  	}
>
> + 	/* write out the notes section */
>  	for(i = 0; i < numnote; i++)
>  		if (!writenote(&notes[i], file))
>  			goto end_coredump;
>
> +	/* write out the thread status notes section */
> +	list_for_each(t, &thread_list) {
> +		struct elf_thread_status *tmp = list_entry(t, struct elf_thread_status,
> list); +		for (i = 0; i < tmp->num_notes; i++)
> +			if (!writenote(&tmp->notes[i], file))
> +				goto end_coredump;
> +	}
> +
>  	DUMP_SEEK(dataoff);
>
>  	for(vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
> @@ -1232,10 +1310,6 @@
>  		if (!maydump(vma))
>  			continue;
>
> -#ifdef DEBUG
> -		printk("elf_core_dump: writing %08lx-%08lx\n", vma->vm_start,
> vma->vm_end); -#endif
> -
>  		for (addr = vma->vm_start;
>  		     addr < vma->vm_end;
>  		     addr += PAGE_SIZE) {
> @@ -1267,11 +1341,19 @@
>  		       (off_t) file->f_pos, offset);
>  	}
>
> - end_coredump:
> +end_coredump:
>  	set_fs(fs);
> -	up_write(&current->mm->mmap_sem);
> +
> +cleanup:
> +	while(!list_empty(&thread_list)) {
> +		struct list_head *tmp = thread_list.next;
> +		list_del(tmp);
> +		kfree(list_entry(tmp, struct elf_thread_status, list));
> +	}
> +
>  	return has_dumped;
>  }
> +
>  #endif		/* USE_ELF_CORE_DUMP */
>
>  static int __init init_elf_binfmt(void)
> --- linux/fs/exec.c.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/fs/exec.c	2002-10-17 10:18:17.000000000 +0200
> @@ -1209,6 +1209,35 @@
>  	*out_ptr = 0;
>  }
>
> +static void zap_threads (struct mm_struct *mm)
> +{
> +	struct task_struct *g, *p;
> +
> +	/* give other threads a chance to run: */
> +	yield();
> +
> +	read_lock(&tasklist_lock);
> +	do_each_thread(g,p)
> +		if (mm == p->mm && !p->core_waiter)
> +			force_sig_specific(SIGKILL, p);
> +	while_each_thread(g,p);
> +	read_unlock(&tasklist_lock);
> +}
> +
> +static void coredump_wait(struct mm_struct *mm)
> +{
> +	DECLARE_WAITQUEUE(wait, current);
> +
> +	atomic_inc(&mm->core_waiters);
> +	add_wait_queue(&mm->core_wait, &wait);
> +	zap_threads(mm);
> +	current->state = TASK_UNINTERRUPTIBLE;
> +	if (atomic_read(&mm->core_waiters) != atomic_read(&mm->mm_users))
> +		schedule();
> +	else
> +		current->state = TASK_RUNNING;
> +}
> +
>  int do_coredump(long signr, struct pt_regs * regs)
>  {
>  	struct linux_binfmt * binfmt;
> @@ -1224,13 +1253,16 @@
>  	if (!current->mm->dumpable)
>  		goto fail;
>  	current->mm->dumpable = 0;
> +	if (down_trylock(&current->mm->core_sem))
> +		BUG();
> +	coredump_wait(current->mm);
>  	if (current->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
> -		goto fail;
> +		goto fail_unlock;
>
>   	format_corename(corename, core_pattern, signr);
>  	file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW, 0600);
>  	if (IS_ERR(file))
> -		goto fail;
> +		goto fail_unlock;
>  	inode = file->f_dentry->d_inode;
>  	if (inode->i_nlink > 1)
>  		goto close_fail;	/* multiple links - don't dump */
> @@ -1250,6 +1282,8 @@
>
>  close_fail:
>  	filp_close(file, NULL);
> +fail_unlock:
> +	up(&current->mm->core_sem);
>  fail:
>  	unlock_kernel();
>  	return retval;
> --- linux/include/linux/elf.h.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/include/linux/elf.h	2002-10-17 09:48:55.000000000 +0200
> @@ -1,6 +1,7 @@
>  #ifndef _LINUX_ELF_H
>  #define _LINUX_ELF_H
>
> +#include <linux/sched.h>
>  #include <linux/types.h>
>  #include <asm/elf.h>
>
> @@ -575,7 +576,8 @@
>  #define NT_PRFPREG	2
>  #define NT_PRPSINFO	3
>  #define NT_TASKSTRUCT	4
> -#define NT_PRFPXREG	20
> +#define NT_PRXFPREG     0x46e62b7f      /* copied from
> gdb5.1/include/elf/common.h */ +
>
>  /* Note header in a PT_NOTE section */
>  typedef struct elf32_note {
> --- linux/include/linux/elfcore.h.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/include/linux/elfcore.h	2002-10-17 09:48:55.000000000 +0200
> @@ -85,4 +85,45 @@
>  #define PRARGSZ ELF_PRARGSZ
>  #endif
>
> +#ifdef __KERNEL__
> +static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct
> pt_regs *regs) +{
> +#ifdef ELF_CORE_COPY_REGS
> +	ELF_CORE_COPY_REGS((*elfregs), regs)
> +#else
> +	BUG_ON(sizeof(*elfregs) != sizeof(*regs));
> +	*(struct pt_regs *)elfregs = *regs;
> +#endif
> +}
> +
> +static inline int elf_core_copy_task_regs(struct task_struct *t,
> elf_gregset_t* elfregs) +{
> +#ifdef ELF_CORE_COPY_TASK_REGS
> +
> +	return ELF_CORE_COPY_TASK_REGS(t, elfregs);
> +#endif
> +	return 0;
> +}
> +
> +extern int dump_fpu (struct pt_regs *, elf_fpregset_t *);
> +
> +static inline int elf_core_copy_task_fpregs(struct task_struct *t,
> elf_fpregset_t *fpu) +{
> +#ifdef ELF_CORE_COPY_FPREGS
> +	return ELF_CORE_COPY_FPREGS(t, fpu);
> +#else
> +	return dump_fpu(NULL, fpu);
> +#endif
> +}
> +
> +#ifdef ELF_CORE_COPY_XFPREGS
> +static inline int elf_core_copy_task_xfpregs(struct task_struct *t,
> elf_fpxregset_t *xfpu) +{
> +	return ELF_CORE_COPY_XFPREGS(t, xfpu);
> +}
> +#endif
> +
> +#endif /* __KERNEL__ */
> +
> +
>  #endif /* _LINUX_ELFCORE_H */
> --- linux/include/linux/sched.h.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/include/linux/sched.h	2002-10-17 09:48:55.000000000 +0200
> @@ -208,6 +208,11 @@
>  	/* Architecture-specific MM context */
>  	mm_context_t context;
>
> +	/* coredumping support */
> +	struct semaphore core_sem;
> +	atomic_t core_waiters;
> +	wait_queue_head_t core_wait;
> +
>  	/* aio bits */
>  	rwlock_t		ioctx_list_lock;
>  	struct kioctx		*ioctx_list;
> @@ -401,6 +406,8 @@
>  	void *journal_info;
>  	struct dentry *proc_dentry;
>  	struct backing_dev_info *backing_dev_info;
> +/* threaded coredumping support */
> +	int core_waiter;
>  };
>
>  extern void __put_task_struct(struct task_struct *tsk);
> @@ -540,6 +547,7 @@
>  extern void notify_parent(struct task_struct *, int);
>  extern void do_notify_parent(struct task_struct *, int);
>  extern void force_sig(int, struct task_struct *);
> +extern void force_sig_specific(int, struct task_struct *);
>  extern int send_sig(int, struct task_struct *, int);
>  extern int __broadcast_thread_group(struct task_struct *p, int sig);
>  extern int kill_pg(pid_t, int, int);
> --- linux/include/asm-ia64/elf.h.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/include/asm-ia64/elf.h	2002-10-17 09:48:55.000000000 +0200
> @@ -65,12 +65,16 @@
>  #define ELF_NGREG	128	/* we really need just 72 but let's leave some
> headroom... */ #define ELF_NFPREG	128	/* f0 and f1 could be omitted, but so
> what... */
>
> +typedef unsigned long elf_fpxregset_t;
> +
>  typedef unsigned long elf_greg_t;
>  typedef elf_greg_t elf_gregset_t[ELF_NGREG];
>
>  typedef struct ia64_fpreg elf_fpreg_t;
>  typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
>
> +
> +
>  struct pt_regs;	/* forward declaration... */
>  extern void ia64_elf_core_copy_regs (struct pt_regs *src, elf_gregset_t
> dst); #define
> ELF_CORE_COPY_REGS(_dest,_regs)	ia64_elf_core_copy_regs(_regs, _dest); @@
> -88,6 +92,14 @@
>  struct elf64_hdr;
>  extern void ia64_set_personality (struct elf64_hdr *elf_ex, int
> ibcs2_interpreter); #define SET_PERSONALITY(ex,
> ibcs2)	ia64_set_personality(&(ex), ibcs2) +
> +extern int dump_task_regs(struct task_struct *, elf_gregset_t *);
> +extern int dump_task_fpu (struct task_struct *, elf_fpregset_t *);
> +
> +#define ELF_CORE_COPY_TASK_REGS(tsk, elf_gregs) dump_task_regs(tsk,
> elf_gregs) +#define ELF_CORE_COPY_FPREGS(tsk, elf_fpregs)
> dump_task_fpu(tsk, elf_fpregs) +
> +
>  #endif
>
>  #endif /* _ASM_IA64_ELF_H */
> --- linux/include/asm-i386/elf.h.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/include/asm-i386/elf.h	2002-10-17 09:48:55.000000000 +0200
> @@ -7,6 +7,7 @@
>
>  #include <asm/ptrace.h>
>  #include <asm/user.h>
> +#include <asm/processor.h>
>
>  #include <linux/utsname.h>
>
> @@ -59,6 +60,9 @@
>
>  /* Wow, the "main" arch needs arch dependent functions too.. :) */
>
> +#define savesegment(seg,value) \
> +	asm volatile("movl %%" #seg ",%0":"=m" (*(int *)&(value)))
> +
>  /* regs is struct pt_regs, pr_reg is elf_gregset_t (which is
>     now struct_user_regs, they are different) */
>
> @@ -72,9 +76,8 @@
>  	pr_reg[6] = regs->eax;				\
>  	pr_reg[7] = regs->xds;				\
>  	pr_reg[8] = regs->xes;				\
> -	/* fake once used fs and gs selectors? */	\
> -	pr_reg[9] = regs->xds;	/* was fs and __fs */	\
> -	pr_reg[10] = regs->xds;	/* was gs and __gs */	\
> +	savesegment(fs,pr_reg[9]);			\
> +	savesegment(gs,pr_reg[10]);			\
>  	pr_reg[11] = regs->orig_eax;			\
>  	pr_reg[12] = regs->eip;				\
>  	pr_reg[13] = regs->xcs;				\
> @@ -99,6 +102,20 @@
>
>  #ifdef __KERNEL__
>  #define SET_PERSONALITY(ex, ibcs2)
> set_personality((ibcs2)?PER_SVR4:PER_LINUX) +
> +extern int dump_task_regs (struct task_struct *, elf_gregset_t *);
> +extern int dump_task_fpu (struct task_struct *, elf_fpregset_t *);
> +extern int dump_task_extended_fpu (struct task_struct *, struct
> user_fxsr_struct *); +
> +#define ELF_CORE_COPY_TASK_REGS(tsk, elf_regs) dump_task_regs(tsk,
> elf_regs) +#define ELF_CORE_COPY_FPREGS(tsk, elf_fpregs) dump_task_fpu(tsk,
> elf_fpregs) +#define ELF_CORE_COPY_XFPREGS(tsk, elf_xfpregs)
> dump_task_extended_fpu(tsk, elf_xfpregs) +
> +#ifdef CONFIG_SMP
> +extern void dump_smp_unlazy_fpu(void);
> +#define ELF_CORE_SYNC dump_smp_unlazy_fpu
> +#endif
> +
>  #endif
>
>  #endif
> --- linux/kernel/exit.c.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/kernel/exit.c	2002-10-17 09:48:55.000000000 +0200
> @@ -416,19 +416,31 @@
>   */
>  static inline void __exit_mm(struct task_struct * tsk)
>  {
> -	struct mm_struct * mm = tsk->mm;
> +	struct mm_struct *mm = tsk->mm;
>
>  	mm_release();
> -	if (mm) {
> -		atomic_inc(&mm->mm_count);
> -		if (mm != tsk->active_mm) BUG();
> -		/* more a memory barrier than a real lock */
> -		task_lock(tsk);
> -		tsk->mm = NULL;
> -		enter_lazy_tlb(mm, current, smp_processor_id());
> -		task_unlock(tsk);
> -		mmput(mm);
> +	if (!mm)
> +		return;
> +	/*
> +	 * Serialize with any possible pending coredump:
> +	 */
> +	if (!mm->dumpable) {
> +		current->core_waiter = 1;
> +		atomic_inc(&mm->core_waiters);
> +		if (atomic_read(&mm->core_waiters) ==atomic_read(&mm->mm_users))
> +			wake_up(&mm->core_wait);
> +		down(&mm->core_sem);
> +		up(&mm->core_sem);
> +		atomic_dec(&mm->core_waiters);
>  	}
> +	atomic_inc(&mm->mm_count);
> +	if (mm != tsk->active_mm) BUG();
> +	/* more a memory barrier than a real lock */
> +	task_lock(tsk);
> +	tsk->mm = NULL;
> +	enter_lazy_tlb(mm, current, smp_processor_id());
> +	task_unlock(tsk);
> +	mmput(mm);
>  }
>
>  void exit_mm(struct task_struct *tsk)
> --- linux/kernel/fork.c.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/kernel/fork.c	2002-10-17 09:48:55.000000000 +0200
> @@ -305,6 +305,9 @@
>  	atomic_set(&mm->mm_users, 1);
>  	atomic_set(&mm->mm_count, 1);
>  	init_rwsem(&mm->mmap_sem);
> +	init_MUTEX(&mm->core_sem);
> +	init_waitqueue_head(&mm->core_wait);
> +	atomic_set(&mm->core_waiters, 0);
>  	mm->page_table_lock = SPIN_LOCK_UNLOCKED;
>  	mm->ioctx_list_lock = RW_LOCK_UNLOCKED;
>  	mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm);
> @@ -771,6 +774,8 @@
>
>  	INIT_LIST_HEAD(&p->local_pages);
>
> +	p->core_waiter = 0;
> +
>  	retval = -ENOMEM;
>  	if (security_ops->task_alloc_security(p))
>  		goto bad_fork_cleanup;
> --- linux/kernel/signal.c.orig	2002-10-17 09:48:47.000000000 +0200
> +++ linux/kernel/signal.c	2002-10-17 09:48:55.000000000 +0200
> @@ -768,7 +768,7 @@
>  }
>
>  static int
> -specific_force_sig_info(int sig, struct task_struct *t)
> +__specific_force_sig_info(int sig, struct task_struct *t)
>  {
>  	if (!t->sig)
>  		return -ESRCH;
> @@ -781,6 +781,20 @@
>  	return specific_send_sig_info(sig, (void *)2, t, 0);
>  }
>
> +void
> +force_sig_specific(int sig, struct task_struct *t)
> +{
> +	unsigned long int flags;
> +
> +	spin_lock_irqsave(&t->sig->siglock, flags);
> +	if (t->sig->action[sig-1].sa.sa_handler == SIG_IGN)
> +		t->sig->action[sig-1].sa.sa_handler = SIG_DFL;
> +	sigdelset(&t->blocked, sig);
> +	recalc_sigpending_tsk(t);
> +	specific_send_sig_info(sig, (void *)2, t, 0);
> +	spin_unlock_irqrestore(&t->sig->siglock, flags);
> +}
> +
>  #define can_take_signal(p, sig)	\
>  	(((unsigned long) p->sig->action[sig-1].sa.sa_handler > 1) && \
>  	!sigismember(&p->blocked, sig) && (task_curr(p) || !signal_pending(p)))
> @@ -846,7 +860,7 @@
>  	int err = 0;
>
>  	for_each_task_pid(p->tgid, PIDTYPE_TGID, tmp, l, pid)
> -		err = specific_force_sig_info(sig, tmp);
> +		err = __specific_force_sig_info(sig, tmp);
>
>  	return err;
>  }
>
> -
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