Hi,
elf_core_dump() uses a stack of > 0x480 bytes (IIRC).
This patch combines several of the large stack items into
one kmalloc-ed area (which has a size of 0x3fc on x86).
Is this a problem?
Builds and produces core files on 2.5.63. :)
TEST log is in metadata below.
gdb can read the core files, but needs more testing, please.
-- ~Randypatch_name: binfmtelf_stack_2563.patch patch_version: 2003-02-27.10:37:04 author: Randy.Dunlap <rddunlap@osdl.org> description: reduce large stack usage in fs/binfmt_elf.c::elf_core_dump(); product: Linux product_versions: linux-2563 changelog: _ testlog: TEST: alloc sizes = 0x34 + 0x90 + 0x7c + 0x6c + 0x200 + 0x50 = 0x3fc TEST: ptr list: mem = f6f82400, elf = f6f82400, prstatus = f6f82434, psinfo = f6f824c4 fpu = f6f82540, xfpu = f6f825ac, notes = f6f827ac URL: _ requires: _ conflicts: _ diffstat: = fs/binfmt_elf.c | 105 ++++++++++++++++++++++++++++++++++++++------------------ 1 files changed, 73 insertions(+), 32 deletions(-)
diff -Naur ./fs/binfmt_elf.c%STK ./fs/binfmt_elf.c --- ./fs/binfmt_elf.c%STK Mon Feb 24 11:05:31 2003 +++ ./fs/binfmt_elf.c Thu Feb 27 10:36:26 2003 @@ -10,7 +10,7 @@ */ #include <linux/module.h> - +#include <linux/kernel.h> #include <linux/fs.h> #include <linux/stat.h> #include <linux/time.h> @@ -1175,40 +1175,79 @@ */ static int elf_core_dump(long signr, struct pt_regs * regs, struct file * file) { +#define NUM_NOTES 5 int has_dumped = 0; mm_segment_t fs; int segs; size_t size = 0; int i; struct vm_area_struct *vma; - struct elfhdr elf; + void *mem; /* aggregation of several large data structures */ + ///struct elfhdr elf; ///52B + struct elfhdr *elf; off_t offset = 0, dataoff; unsigned long limit = current->rlim[RLIMIT_CORE].rlim_cur; - int numnote = 5; - struct memelfnote notes[5]; - struct elf_prstatus prstatus; /* NT_PRSTATUS */ - struct elf_prpsinfo psinfo; /* NT_PRPSINFO */ + int numnote = NUM_NOTES; + ///struct memelfnote notes[5]; ///16*5=80B + struct memelfnote *notes[NUM_NOTES]; + ///struct elf_prstatus prstatus; /* NT_PRSTATUS */ ///80B + struct elf_prstatus *prstatus; /* NT_PRSTATUS */ + ///struct elf_prpsinfo psinfo; /* NT_PRPSINFO */ ///128B + struct elf_prpsinfo *psinfo; /* NT_PRPSINFO */ struct task_struct *g, *p; LIST_HEAD(thread_list); struct list_head *t; - elf_fpregset_t fpu; + ///elf_fpregset_t fpu; ///108B + elf_fpregset_t *fpu; + ///elf_fpxregset_t xfpu; ///kmalloc:512B + elf_fpxregset_t *xfpu; #ifdef ELF_CORE_COPY_XFPREGS - elf_fpxregset_t xfpu; + int xfpu_size = sizeof(*xfpu); +#else + int xfpu_size = 0; #endif int thread_status_size = 0; - - /* We no longer stop all vm operations + + /* + * 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 is 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. - * + * the map_count or the pages allocated. So no possibility of crashing + * exists while dumping the mm->vm_next areas to the core file. */ - + + /* alloc memory for large data structures */ + mem = kmalloc(sizeof(*elf) + + sizeof(*prstatus)+ sizeof(*psinfo) + + sizeof(*fpu) + xfpu_size + + ARRAY_SIZE(notes) * sizeof(struct memelfnote), + GFP_KERNEL); + if (!mem) + goto cleanup; + + elf = mem; + prstatus = (void *)elf + sizeof(*elf); + psinfo = (void *)prstatus + sizeof(*prstatus); + fpu = (void *)psinfo + sizeof(*psinfo); + xfpu = (void *)fpu + sizeof(*fpu); + for (i = 0; i < NUM_NOTES; i++) { + notes[i] = (void *)xfpu + xfpu_size + i * sizeof(struct memelfnote); + } + /* TEST: printk() these ptrs/sizes and total size of mem; */ + printk ("TEST: alloc sizes = 0x%x + 0x%x + 0x%x + 0x%x + 0x%x + 0x%x = 0x%x\n", + sizeof(*elf), sizeof(*prstatus), sizeof(*psinfo), + sizeof(*fpu), xfpu_size, + NUM_NOTES * sizeof(struct memelfnote), + sizeof(*elf)+ sizeof(*prstatus)+ sizeof(*psinfo)+ + sizeof(*fpu)+ xfpu_size+ + NUM_NOTES * sizeof(struct memelfnote)); + printk ("TEST: ptr list: mem = %p, elf = %p, prstatus = %p, psinfo = %p\n fpu = %p, xfpu = %p, notes = %p\n", + mem, elf, prstatus, psinfo, fpu, xfpu, notes[0]); + /* capture the status of all other threads */ if (signr) { read_lock(&tasklist_lock); @@ -1226,14 +1265,14 @@ } /* 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); + memset(prstatus, 0, sizeof(*prstatus)); + fill_prstatus(prstatus, current, signr); + elf_core_copy_regs(&prstatus->pr_reg, regs); segs = current->mm->map_count; /* Set up header */ - fill_elf_header(&elf, segs+1); /* including notes section*/ + fill_elf_header(elf, segs+1); /* including notes section*/ has_dumped = 1; current->flags |= PF_DUMPCORE; @@ -1243,21 +1282,21 @@ * with info from their /proc. */ - fill_note(¬es[0], "CORE", NT_PRSTATUS, sizeof(prstatus), &prstatus); + fill_note(notes[0], "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus); - fill_psinfo(&psinfo, current->group_leader); - fill_note(¬es[1], "CORE", NT_PRPSINFO, sizeof(psinfo), &psinfo); + fill_psinfo(psinfo, current->group_leader); + fill_note(notes[1], "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo); - fill_note(¬es[2], "CORE", NT_TASKSTRUCT, sizeof(*current), current); + 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(¬es[3], "CORE", NT_PRFPREG, sizeof(fpu), &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(¬es[4], "LINUX", NT_PRXFPREG, sizeof(xfpu), &xfpu); + if (elf_core_copy_task_xfpregs(current, xfpu)) + fill_note(notes[4], "LINUX", NT_PRXFPREG, sizeof(*xfpu), xfpu); else --numnote; #else @@ -1267,8 +1306,8 @@ fs = get_fs(); set_fs(KERNEL_DS); - DUMP_WRITE(&elf, sizeof(elf)); - offset += sizeof(elf); /* Elf header */ + DUMP_WRITE(elf, sizeof(*elf)); + offset += sizeof(*elf); /* Elf header */ offset += (segs+1) * sizeof(struct elf_phdr); /* Program headers */ /* Write notes phdr entry */ @@ -1277,7 +1316,7 @@ int sz = 0; for(i = 0; i < numnote; i++) - sz += notesize(¬es[i]); + sz += notesize(notes[i]); sz += thread_status_size; @@ -1313,7 +1352,7 @@ /* write out the notes section */ for(i = 0; i < numnote; i++) - if (!writenote(¬es[i], file)) + if (!writenote(notes[i], file)) goto end_coredump; /* write out the thread status notes section */ @@ -1373,7 +1412,9 @@ kfree(list_entry(tmp, struct elf_thread_status, list)); } + kfree(mem); return has_dumped; +#undef NUM_NOTES } #endif /* USE_ELF_CORE_DUMP */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Feb 28 2003 - 22:00:44 EST