diff options
| -rw-r--r-- | fs/proc/vmcore.c | 247 |
1 files changed, 243 insertions, 4 deletions
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index abb3dba0fa49..247c3499e5bd 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -39,6 +39,8 @@ static size_t elfcorebuf_sz_orig; static char *elfnotes_buf; static size_t elfnotes_sz; +/* Size of all notes minus the device dump notes */ +static size_t elfnotes_orig_sz; /* Total size of vmcore file. */ static u64 vmcore_size; @@ -51,6 +53,9 @@ static LIST_HEAD(vmcoredd_list); static DEFINE_MUTEX(vmcoredd_mutex); #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ +/* Device Dump Size */ +static size_t vmcoredd_orig_sz; + /* * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error * The called function has to take care of module refcounting. @@ -185,6 +190,77 @@ static int copy_to(void *target, void *src, size_t size, int userbuf) return 0; } +#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP +static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf) +{ + struct vmcoredd_node *dump; + u64 offset = 0; + int ret = 0; + size_t tsz; + char *buf; + + mutex_lock(&vmcoredd_mutex); + list_for_each_entry(dump, &vmcoredd_list, list) { + if (start < offset + dump->size) { + tsz = min(offset + (u64)dump->size - start, (u64)size); + buf = dump->buf + start - offset; + if (copy_to(dst, buf, tsz, userbuf)) { + ret = -EFAULT; + goto out_unlock; + } + + size -= tsz; + start += tsz; + dst += tsz; + + /* Leave now if buffer filled already */ + if (!size) + goto out_unlock; + } + offset += dump->size; + } + +out_unlock: + mutex_unlock(&vmcoredd_mutex); + return ret; +} + +static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst, + u64 start, size_t size) +{ + struct vmcoredd_node *dump; + u64 offset = 0; + int ret = 0; + size_t tsz; + char *buf; + + mutex_lock(&vmcoredd_mutex); + list_for_each_entry(dump, &vmcoredd_list, list) { + if (start < offset + dump->size) { + tsz = min(offset + (u64)dump->size - start, (u64)size); + buf = dump->buf + start - offset; + if (remap_vmalloc_range_partial(vma, dst, buf, tsz)) { + ret = -EFAULT; + goto out_unlock; + } + + size -= tsz; + start += tsz; + dst += tsz; + + /* Leave now if buffer filled already */ + if (!size) + goto out_unlock; + } + offset += dump->size; + } + +out_unlock: + mutex_unlock(&vmcoredd_mutex); + return ret; +} +#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ + /* Read from the ELF header and then the crash dump. On error, negative value is * returned otherwise number of bytes read are returned. */ @@ -222,10 +298,41 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos, if (*fpos < elfcorebuf_sz + elfnotes_sz) { void *kaddr; + /* We add device dumps before other elf notes because the + * other elf notes may not fill the elf notes buffer + * completely and we will end up with zero-filled data + * between the elf notes and the device dumps. Tools will + * then try to decode this zero-filled data as valid notes + * and we don't want that. Hence, adding device dumps before + * the other elf notes ensure that zero-filled data can be + * avoided. + */ +#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP + /* Read device dumps */ + if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) { + tsz = min(elfcorebuf_sz + vmcoredd_orig_sz - + (size_t)*fpos, buflen); + start = *fpos - elfcorebuf_sz; + if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf)) + return -EFAULT; + + buflen -= tsz; + *fpos += tsz; + buffer += tsz; + acc += tsz; + + /* leave now if filled buffer already */ + if (!buflen) + return acc; + } +#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ + + /* Read remaining elf notes */ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen); - kaddr = elfnotes_buf + *fpos - elfcorebuf_sz; + kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz; if (copy_to(buffer, kaddr, tsz, userbuf)) return -EFAULT; + buflen -= tsz; *fpos += tsz; buffer += tsz; @@ -451,11 +558,46 @@ static int mmap_vmcore(struct file *file, struct vm_area_struct *vma) if (start < elfcorebuf_sz + elfnotes_sz) { void *kaddr; + /* We add device dumps before other elf notes because the + * other elf notes may not fill the elf notes buffer + * completely and we will end up with zero-filled data + * between the elf notes and the device dumps. Tools will + * then try to decode this zero-filled data as valid notes + * and we don't want that. Hence, adding device dumps before + * the other elf notes ensure that zero-filled data can be + * avoided. This also ensures that the device dumps and + * other elf notes can be properly mmaped at page aligned + * address. + */ +#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP + /* Read device dumps */ + if (start < elfcorebuf_sz + vmcoredd_orig_sz) { + u64 start_off; + + tsz = min(elfcorebuf_sz + vmcoredd_orig_sz - + (size_t)start, size); + start_off = start - elfcorebuf_sz; + if (vmcoredd_mmap_dumps(vma, vma->vm_start + len, + start_off, tsz)) + goto fail; + + size -= tsz; + start += tsz; + len += tsz; + + /* leave now if filled buffer already */ + if (!size) + return 0; + } +#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ + + /* Read remaining elf notes */ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size); - kaddr = elfnotes_buf + start - elfcorebuf_sz; + kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz; if (remap_vmalloc_range_partial(vma, vma->vm_start + len, kaddr, tsz)) goto fail; + size -= tsz; start += tsz; len += tsz; @@ -703,6 +845,11 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz, /* Modify e_phnum to reflect merged headers. */ ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1; + /* Store the size of all notes. We need this to update the note + * header when the device dumps will be added. + */ + elfnotes_orig_sz = phdr.p_memsz; + return 0; } @@ -889,6 +1036,11 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz, /* Modify e_phnum to reflect merged headers. */ ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1; + /* Store the size of all notes. We need this to update the note + * header when the device dumps will be added. + */ + elfnotes_orig_sz = phdr.p_memsz; + return 0; } @@ -981,8 +1133,8 @@ static int __init process_ptload_program_headers_elf32(char *elfptr, } /* Sets offset fields of vmcore elements. */ -static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz, - struct list_head *vc_list) +static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz, + struct list_head *vc_list) { loff_t vmcore_off; struct vmcore *m; @@ -1175,6 +1327,92 @@ static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data, } /** + * vmcoredd_update_program_headers - Update all Elf program headers + * @elfptr: Pointer to elf header + * @elfnotesz: Size of elf notes aligned to page size + * @vmcoreddsz: Size of device dumps to be added to elf note header + * + * Determine type of Elf header (Elf64 or Elf32) and update the elf note size. + * Also update the offsets of all the program headers after the elf note header. + */ +static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz, + size_t vmcoreddsz) +{ + unsigned char *e_ident = (unsigned char *)elfptr; + u64 start, end, size; + loff_t vmcore_off; + u32 i; + + vmcore_off = elfcorebuf_sz + elfnotesz; + + if (e_ident[EI_CLASS] == ELFCLASS64) { + Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr; + Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr)); + + /* Update all program headers */ + for (i = 0; i < ehdr->e_phnum; i++, phdr++) { + if (phdr->p_type == PT_NOTE) { + /* Update note size */ + phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz; + phdr->p_filesz = phdr->p_memsz; + continue; + } + + start = rounddown(phdr->p_offset, PAGE_SIZE); + end = roundup(phdr->p_offset + phdr->p_memsz, + PAGE_SIZE); + size = end - start; + phdr->p_offset = vmcore_off + (phdr->p_offset - start); + vmcore_off += size; + } + } else { + Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr; + Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr)); + + /* Update all program headers */ + for (i = 0; i < ehdr->e_phnum; i++, phdr++) { + if (phdr->p_type == PT_NOTE) { + /* Update note size */ + phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz; + phdr->p_filesz = phdr->p_memsz; + continue; + } + + start = rounddown(phdr->p_offset, PAGE_SIZE); + end = roundup(phdr->p_offset + phdr->p_memsz, + PAGE_SIZE); + size = end - start; + phdr->p_offset = vmcore_off + (phdr->p_offset - start); + vmcore_off += size; + } + } +} + +/** + * vmcoredd_update_size - Update the total size of the device dumps and update + * Elf header + * @dump_size: Size of the current device dump to be added to total size + * + * Update the total size of all the device dumps and update the Elf program + * headers. Calculate the new offsets for the vmcore list and update the + * total vmcore size. + */ +static void vmcoredd_update_size(size_t dump_size) +{ + vmcoredd_orig_sz += dump_size; + elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz; + vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz, + vmcoredd_orig_sz); + + /* Update vmcore list offsets */ + set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list); + + vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz, + &vmcore_list); + proc_vmcore->size = vmcore_size; +} + +/** * vmcore_add_device_dump - Add a buffer containing device dump to vmcore * @data: dump info. * @@ -1227,6 +1465,7 @@ int vmcore_add_device_dump(struct vmcoredd_data *data) list_add_tail(&dump->list, &vmcoredd_list); mutex_unlock(&vmcoredd_mutex); + vmcoredd_update_size(data_size); return 0; out_err: |