diff options
| -rw-r--r-- | fs/coredump.c | 45 | ||||
| -rw-r--r-- | include/linux/uio.h | 16 | ||||
| -rw-r--r-- | lib/iov_iter.c | 23 |
3 files changed, 42 insertions, 42 deletions
diff --git a/fs/coredump.c b/fs/coredump.c index f258c17c1841..be6403b4b14b 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -872,6 +872,9 @@ static int dump_emit_page(struct coredump_params *cprm, struct page *page) loff_t pos; ssize_t n; + if (!page) + return 0; + if (cprm->to_skip) { if (!__dump_skip(cprm, cprm->to_skip)) return 0; @@ -884,7 +887,6 @@ static int dump_emit_page(struct coredump_params *cprm, struct page *page) pos = file->f_pos; bvec_set_page(&bvec, page, PAGE_SIZE, 0); iov_iter_bvec(&iter, ITER_SOURCE, &bvec, 1, PAGE_SIZE); - iov_iter_set_copy_mc(&iter); n = __kernel_write_iter(cprm->file, &iter, &pos); if (n != PAGE_SIZE) return 0; @@ -895,10 +897,44 @@ static int dump_emit_page(struct coredump_params *cprm, struct page *page) return 1; } +/* + * If we might get machine checks from kernel accesses during the + * core dump, let's get those errors early rather than during the + * IO. This is not performance-critical enough to warrant having + * all the machine check logic in the iovec paths. + */ +#ifdef copy_mc_to_kernel + +#define dump_page_alloc() alloc_page(GFP_KERNEL) +#define dump_page_free(x) __free_page(x) +static struct page *dump_page_copy(struct page *src, struct page *dst) +{ + void *buf = kmap_local_page(src); + size_t left = copy_mc_to_kernel(page_address(dst), buf, PAGE_SIZE); + kunmap_local(buf); + return left ? NULL : dst; +} + +#else + +/* We just want to return non-NULL; it's never used. */ +#define dump_page_alloc() ERR_PTR(-EINVAL) +#define dump_page_free(x) ((void)(x)) +static inline struct page *dump_page_copy(struct page *src, struct page *dst) +{ + return src; +} +#endif + int dump_user_range(struct coredump_params *cprm, unsigned long start, unsigned long len) { unsigned long addr; + struct page *dump_page; + + dump_page = dump_page_alloc(); + if (!dump_page) + return 0; for (addr = start; addr < start + len; addr += PAGE_SIZE) { struct page *page; @@ -912,14 +948,17 @@ int dump_user_range(struct coredump_params *cprm, unsigned long start, */ page = get_dump_page(addr); if (page) { - int stop = !dump_emit_page(cprm, page); + int stop = !dump_emit_page(cprm, dump_page_copy(page, dump_page)); put_page(page); - if (stop) + if (stop) { + dump_page_free(dump_page); return 0; + } } else { dump_skip(cprm, PAGE_SIZE); } } + dump_page_free(dump_page); return 1; } #endif diff --git a/include/linux/uio.h b/include/linux/uio.h index bea9c89922d9..00cebe2b70de 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -40,7 +40,6 @@ struct iov_iter_state { struct iov_iter { u8 iter_type; - bool copy_mc; bool nofault; bool data_source; size_t iov_offset; @@ -248,22 +247,8 @@ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); #ifdef CONFIG_ARCH_HAS_COPY_MC size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i); -static inline void iov_iter_set_copy_mc(struct iov_iter *i) -{ - i->copy_mc = true; -} - -static inline bool iov_iter_is_copy_mc(const struct iov_iter *i) -{ - return i->copy_mc; -} #else #define _copy_mc_to_iter _copy_to_iter -static inline void iov_iter_set_copy_mc(struct iov_iter *i) { } -static inline bool iov_iter_is_copy_mc(const struct iov_iter *i) -{ - return false; -} #endif size_t iov_iter_zero(size_t bytes, struct iov_iter *); @@ -355,7 +340,6 @@ static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction, WARN_ON(direction & ~(READ | WRITE)); *i = (struct iov_iter) { .iter_type = ITER_UBUF, - .copy_mc = false, .data_source = direction, .ubuf = buf, .count = count, diff --git a/lib/iov_iter.c b/lib/iov_iter.c index e0aa6b440ca5..cf2eb2b2f983 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -166,7 +166,6 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, WARN_ON(direction & ~(READ | WRITE)); *i = (struct iov_iter) { .iter_type = ITER_IOVEC, - .copy_mc = false, .nofault = false, .data_source = direction, .__iov = iov, @@ -245,26 +244,8 @@ EXPORT_SYMBOL_GPL(_copy_mc_to_iter); #endif /* CONFIG_ARCH_HAS_COPY_MC */ static __always_inline -size_t memcpy_from_iter_mc(void *iter_from, size_t progress, - size_t len, void *to, void *priv2) -{ - return copy_mc_to_kernel(to + progress, iter_from, len); -} - -static size_t __copy_from_iter_mc(void *addr, size_t bytes, struct iov_iter *i) -{ - if (unlikely(i->count < bytes)) - bytes = i->count; - if (unlikely(!bytes)) - return 0; - return iterate_bvec(i, bytes, addr, NULL, memcpy_from_iter_mc); -} - -static __always_inline size_t __copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) { - if (unlikely(iov_iter_is_copy_mc(i))) - return __copy_from_iter_mc(addr, bytes, i); return iterate_and_advance(i, bytes, addr, copy_from_user_iter, memcpy_from_iter); } @@ -633,7 +614,6 @@ void iov_iter_kvec(struct iov_iter *i, unsigned int direction, WARN_ON(direction & ~(READ | WRITE)); *i = (struct iov_iter){ .iter_type = ITER_KVEC, - .copy_mc = false, .data_source = direction, .kvec = kvec, .nr_segs = nr_segs, @@ -650,7 +630,6 @@ void iov_iter_bvec(struct iov_iter *i, unsigned int direction, WARN_ON(direction & ~(READ | WRITE)); *i = (struct iov_iter){ .iter_type = ITER_BVEC, - .copy_mc = false, .data_source = direction, .bvec = bvec, .nr_segs = nr_segs, @@ -679,7 +658,6 @@ void iov_iter_xarray(struct iov_iter *i, unsigned int direction, BUG_ON(direction & ~1); *i = (struct iov_iter) { .iter_type = ITER_XARRAY, - .copy_mc = false, .data_source = direction, .xarray = xarray, .xarray_start = start, @@ -703,7 +681,6 @@ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) BUG_ON(direction != READ); *i = (struct iov_iter){ .iter_type = ITER_DISCARD, - .copy_mc = false, .data_source = false, .count = count, .iov_offset = 0 |