diff options
| -rw-r--r-- | lib/buildid.c | 54 |
1 files changed, 35 insertions, 19 deletions
diff --git a/lib/buildid.c b/lib/buildid.c index c1cbd34f3685..18ef55812c64 100644 --- a/lib/buildid.c +++ b/lib/buildid.c @@ -16,10 +16,11 @@ struct freader { int err; union { struct { - struct address_space *mapping; + struct file *file; struct folio *folio; void *addr; loff_t folio_off; + bool may_fault; }; struct { const char *data; @@ -29,12 +30,13 @@ struct freader { }; static void freader_init_from_file(struct freader *r, void *buf, u32 buf_sz, - struct address_space *mapping) + struct file *file, bool may_fault) { memset(r, 0, sizeof(*r)); r->buf = buf; r->buf_sz = buf_sz; - r->mapping = mapping; + r->file = file; + r->may_fault = may_fault; } static void freader_init_from_mem(struct freader *r, const char *data, u64 data_sz) @@ -62,7 +64,16 @@ static int freader_get_folio(struct freader *r, loff_t file_off) freader_put_folio(r); - r->folio = filemap_get_folio(r->mapping, file_off >> PAGE_SHIFT); + r->folio = filemap_get_folio(r->file->f_mapping, file_off >> PAGE_SHIFT); + + /* if sleeping is allowed, wait for the page, if necessary */ + if (r->may_fault && (IS_ERR(r->folio) || !folio_test_uptodate(r->folio))) { + filemap_invalidate_lock_shared(r->file->f_mapping); + r->folio = read_cache_folio(r->file->f_mapping, file_off >> PAGE_SHIFT, + NULL, r->file); + filemap_invalidate_unlock_shared(r->file->f_mapping); + } + if (IS_ERR(r->folio) || !folio_test_uptodate(r->folio)) { if (!IS_ERR(r->folio)) folio_put(r->folio); @@ -287,18 +298,8 @@ static int get_build_id_64(struct freader *r, unsigned char *build_id, __u32 *si /* enough for Elf64_Ehdr, Elf64_Phdr, and all the smaller requests */ #define MAX_FREADER_BUF_SZ 64 -/* - * Parse build ID of ELF file mapped to vma - * @vma: vma object - * @build_id: buffer to store build id, at least BUILD_ID_SIZE long - * @size: returns actual build id size in case of success - * - * Assumes no page fault can be taken, so if relevant portions of ELF file are - * not already paged in, fetching of build ID fails. - * - * Return: 0 on success; negative error, otherwise - */ -int build_id_parse_nofault(struct vm_area_struct *vma, unsigned char *build_id, __u32 *size) +static int __build_id_parse(struct vm_area_struct *vma, unsigned char *build_id, + __u32 *size, bool may_fault) { const Elf32_Ehdr *ehdr; struct freader r; @@ -309,7 +310,7 @@ int build_id_parse_nofault(struct vm_area_struct *vma, unsigned char *build_id, if (!vma->vm_file) return -EINVAL; - freader_init_from_file(&r, buf, sizeof(buf), vma->vm_file->f_mapping); + freader_init_from_file(&r, buf, sizeof(buf), vma->vm_file, may_fault); /* fetch first 18 bytes of ELF header for checks */ ehdr = freader_fetch(&r, 0, offsetofend(Elf32_Ehdr, e_type)); @@ -338,6 +339,22 @@ out: } /* + * Parse build ID of ELF file mapped to vma + * @vma: vma object + * @build_id: buffer to store build id, at least BUILD_ID_SIZE long + * @size: returns actual build id size in case of success + * + * Assumes no page fault can be taken, so if relevant portions of ELF file are + * not already paged in, fetching of build ID fails. + * + * Return: 0 on success; negative error, otherwise + */ +int build_id_parse_nofault(struct vm_area_struct *vma, unsigned char *build_id, __u32 *size) +{ + return __build_id_parse(vma, build_id, size, false /* !may_fault */); +} + +/* * Parse build ID of ELF file mapped to VMA * @vma: vma object * @build_id: buffer to store build id, at least BUILD_ID_SIZE long @@ -350,8 +367,7 @@ out: */ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id, __u32 *size) { - /* fallback to non-faultable version for now */ - return build_id_parse_nofault(vma, build_id, size); + return __build_id_parse(vma, build_id, size, true /* may_fault */); } /** |