elf core dump: notes user_regset
This modifies the ELF core dump code under #ifdef CORE_DUMP_USE_REGSET. It changes nothing when this macro is not defined. When it's #define'd by some arch header (e.g. asm/elf.h), the arch must support the user_regset (linux/regset.h) interface for reading thread state. This provides an alternate version of note segment writing that is based purely on the user_regset interfaces. When CORE_DUMP_USE_REGSET is set, the arch need not define macros such as ELF_CORE_COPY_REGS and ELF_ARCH. All that information is taken from the user_regset data structures. The core dumps come out exactly the same if arch's definitions for its user_regset details are correct. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath
Ingo Molnar
parent
3aba481fc9
commit
4206d3aa19
1 changed files with 224 additions and 0 deletions
224
fs/binfmt_elf.c
224
fs/binfmt_elf.c
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@ -1528,6 +1528,228 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
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fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
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}
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#ifdef CORE_DUMP_USE_REGSET
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#include <linux/regset.h>
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struct elf_thread_core_info {
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struct elf_thread_core_info *next;
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struct task_struct *task;
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struct elf_prstatus prstatus;
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struct memelfnote notes[0];
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};
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struct elf_note_info {
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struct elf_thread_core_info *thread;
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struct memelfnote psinfo;
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struct memelfnote auxv;
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size_t size;
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int thread_notes;
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};
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static int fill_thread_core_info(struct elf_thread_core_info *t,
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const struct user_regset_view *view,
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long signr, size_t *total)
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{
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unsigned int i;
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/*
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* NT_PRSTATUS is the one special case, because the regset data
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* goes into the pr_reg field inside the note contents, rather
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* than being the whole note contents. We fill the reset in here.
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* We assume that regset 0 is NT_PRSTATUS.
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*/
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fill_prstatus(&t->prstatus, t->task, signr);
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(void) view->regsets[0].get(t->task, &view->regsets[0],
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0, sizeof(t->prstatus.pr_reg),
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&t->prstatus.pr_reg, NULL);
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fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
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sizeof(t->prstatus), &t->prstatus);
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*total += notesize(&t->notes[0]);
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/*
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* Each other regset might generate a note too. For each regset
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* that has no core_note_type or is inactive, we leave t->notes[i]
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* all zero and we'll know to skip writing it later.
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*/
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for (i = 1; i < view->n; ++i) {
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const struct user_regset *regset = &view->regsets[i];
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if (regset->core_note_type &&
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(!regset->active || regset->active(t->task, regset))) {
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int ret;
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size_t size = regset->n * regset->size;
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void *data = kmalloc(size, GFP_KERNEL);
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if (unlikely(!data))
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return 0;
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ret = regset->get(t->task, regset,
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0, size, data, NULL);
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if (unlikely(ret))
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kfree(data);
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else {
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if (regset->core_note_type != NT_PRFPREG)
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fill_note(&t->notes[i], "LINUX",
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regset->core_note_type,
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size, data);
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else {
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t->prstatus.pr_fpvalid = 1;
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fill_note(&t->notes[i], "CORE",
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NT_PRFPREG, size, data);
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}
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*total += notesize(&t->notes[i]);
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}
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}
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}
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return 1;
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}
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static int fill_note_info(struct elfhdr *elf, int phdrs,
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struct elf_note_info *info,
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long signr, struct pt_regs *regs)
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{
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struct task_struct *dump_task = current;
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const struct user_regset_view *view = task_user_regset_view(dump_task);
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struct elf_thread_core_info *t;
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struct elf_prpsinfo *psinfo;
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struct task_struct *g, *p;
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unsigned int i;
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info->size = 0;
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info->thread = NULL;
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psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
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fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
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if (psinfo == NULL)
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return 0;
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/*
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* Figure out how many notes we're going to need for each thread.
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*/
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info->thread_notes = 0;
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for (i = 0; i < view->n; ++i)
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if (view->regsets[i].core_note_type != 0)
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++info->thread_notes;
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/*
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* Sanity check. We rely on regset 0 being in NT_PRSTATUS,
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* since it is our one special case.
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*/
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if (unlikely(info->thread_notes == 0) ||
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unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
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WARN_ON(1);
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return 0;
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}
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/*
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* Initialize the ELF file header.
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*/
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fill_elf_header(elf, phdrs,
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view->e_machine, view->e_flags, view->ei_osabi);
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/*
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* Allocate a structure for each thread.
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*/
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rcu_read_lock();
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do_each_thread(g, p)
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if (p->mm == dump_task->mm) {
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t = kzalloc(offsetof(struct elf_thread_core_info,
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notes[info->thread_notes]),
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GFP_ATOMIC);
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if (unlikely(!t)) {
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rcu_read_unlock();
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return 0;
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}
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t->task = p;
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if (p == dump_task || !info->thread) {
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t->next = info->thread;
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info->thread = t;
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} else {
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/*
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* Make sure to keep the original task at
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* the head of the list.
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*/
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t->next = info->thread->next;
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info->thread->next = t;
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}
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}
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while_each_thread(g, p);
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rcu_read_unlock();
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/*
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* Now fill in each thread's information.
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*/
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for (t = info->thread; t != NULL; t = t->next)
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if (!fill_thread_core_info(t, view, signr, &info->size))
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return 0;
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/*
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* Fill in the two process-wide notes.
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*/
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fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
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info->size += notesize(&info->psinfo);
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fill_auxv_note(&info->auxv, current->mm);
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info->size += notesize(&info->auxv);
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return 1;
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}
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static size_t get_note_info_size(struct elf_note_info *info)
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{
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return info->size;
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}
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/*
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* Write all the notes for each thread. When writing the first thread, the
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* process-wide notes are interleaved after the first thread-specific note.
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*/
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static int write_note_info(struct elf_note_info *info,
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struct file *file, loff_t *foffset)
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{
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bool first = 1;
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struct elf_thread_core_info *t = info->thread;
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do {
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int i;
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if (!writenote(&t->notes[0], file, foffset))
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return 0;
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if (first && !writenote(&info->psinfo, file, foffset))
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return 0;
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if (first && !writenote(&info->auxv, file, foffset))
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return 0;
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for (i = 1; i < info->thread_notes; ++i)
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if (t->notes[i].data &&
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!writenote(&t->notes[i], file, foffset))
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return 0;
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first = 0;
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t = t->next;
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} while (t);
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return 1;
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}
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static void free_note_info(struct elf_note_info *info)
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{
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struct elf_thread_core_info *threads = info->thread;
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while (threads) {
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unsigned int i;
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struct elf_thread_core_info *t = threads;
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threads = t->next;
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WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
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for (i = 1; i < info->thread_notes; ++i)
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kfree(t->notes[i].data);
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kfree(t);
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}
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kfree(info->psinfo.data);
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}
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#else
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/* Here is the structure in which status of each thread is captured. */
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struct elf_thread_status
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{
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@ -1748,6 +1970,8 @@ static void free_note_info(struct elf_note_info *info)
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#endif
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}
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#endif
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static struct vm_area_struct *first_vma(struct task_struct *tsk,
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struct vm_area_struct *gate_vma)
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{
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