Mercurial > hg > nginx
view src/core/ngx_slab.c @ 6957:83bae3d354ab
HTTP/2: fixed connection finalization.
All streams in connection must be finalized before the connection
itself can be finalized and all related memory is freed. That's
not always possible on the current event loop iteration.
Thus when the last stream is finalized, it sets the special read
event handler ngx_http_v2_handle_connection_handler() and posts
the event.
Previously, this handler didn't check the connection state and
could call the regular event handler on a connection that was
already in finalization stage. In the worst case that could
lead to a segmentation fault, since some data structures aren't
supposed to be used during connection finalization. Particularly,
the waiting queue can contain already freed streams, so the
WINDOW_UPDATE frame received by that moment could trigger
accessing to these freed streams.
Now, the connection error flag is explicitly checked in
ngx_http_v2_handle_connection_handler().
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Wed, 29 Mar 2017 20:21:01 +0300 |
parents | e4590dfd97ff |
children | 94f30939545a |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #define NGX_SLAB_PAGE_MASK 3 #define NGX_SLAB_PAGE 0 #define NGX_SLAB_BIG 1 #define NGX_SLAB_EXACT 2 #define NGX_SLAB_SMALL 3 #if (NGX_PTR_SIZE == 4) #define NGX_SLAB_PAGE_FREE 0 #define NGX_SLAB_PAGE_BUSY 0xffffffff #define NGX_SLAB_PAGE_START 0x80000000 #define NGX_SLAB_SHIFT_MASK 0x0000000f #define NGX_SLAB_MAP_MASK 0xffff0000 #define NGX_SLAB_MAP_SHIFT 16 #define NGX_SLAB_BUSY 0xffffffff #else /* (NGX_PTR_SIZE == 8) */ #define NGX_SLAB_PAGE_FREE 0 #define NGX_SLAB_PAGE_BUSY 0xffffffffffffffff #define NGX_SLAB_PAGE_START 0x8000000000000000 #define NGX_SLAB_SHIFT_MASK 0x000000000000000f #define NGX_SLAB_MAP_MASK 0xffffffff00000000 #define NGX_SLAB_MAP_SHIFT 32 #define NGX_SLAB_BUSY 0xffffffffffffffff #endif #define ngx_slab_slots(pool) \ (ngx_slab_page_t *) ((u_char *) (pool) + sizeof(ngx_slab_pool_t)) #define ngx_slab_page_type(page) ((page)->prev & NGX_SLAB_PAGE_MASK) #define ngx_slab_page_prev(page) \ (ngx_slab_page_t *) ((page)->prev & ~NGX_SLAB_PAGE_MASK) #define ngx_slab_page_addr(pool, page) \ ((((page) - (pool)->pages) << ngx_pagesize_shift) \ + (uintptr_t) (pool)->start) #if (NGX_DEBUG_MALLOC) #define ngx_slab_junk(p, size) ngx_memset(p, 0xA5, size) #elif (NGX_HAVE_DEBUG_MALLOC) #define ngx_slab_junk(p, size) \ if (ngx_debug_malloc) ngx_memset(p, 0xA5, size) #else #define ngx_slab_junk(p, size) #endif static ngx_slab_page_t *ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages); static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page, ngx_uint_t pages); static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text); static ngx_uint_t ngx_slab_max_size; static ngx_uint_t ngx_slab_exact_size; static ngx_uint_t ngx_slab_exact_shift; void ngx_slab_init(ngx_slab_pool_t *pool) { u_char *p; size_t size; ngx_int_t m; ngx_uint_t i, n, pages; ngx_slab_page_t *slots, *page; /* STUB */ if (ngx_slab_max_size == 0) { ngx_slab_max_size = ngx_pagesize / 2; ngx_slab_exact_size = ngx_pagesize / (8 * sizeof(uintptr_t)); for (n = ngx_slab_exact_size; n >>= 1; ngx_slab_exact_shift++) { /* void */ } } /**/ pool->min_size = (size_t) 1 << pool->min_shift; slots = ngx_slab_slots(pool); p = (u_char *) slots; size = pool->end - p; ngx_slab_junk(p, size); n = ngx_pagesize_shift - pool->min_shift; for (i = 0; i < n; i++) { /* only "next" is used in list head */ slots[i].slab = 0; slots[i].next = &slots[i]; slots[i].prev = 0; } p += n * sizeof(ngx_slab_page_t); pool->stats = (ngx_slab_stat_t *) p; ngx_memzero(pool->stats, n * sizeof(ngx_slab_stat_t)); p += n * sizeof(ngx_slab_stat_t); size -= n * (sizeof(ngx_slab_page_t) + sizeof(ngx_slab_stat_t)); pages = (ngx_uint_t) (size / (ngx_pagesize + sizeof(ngx_slab_page_t))); pool->pages = (ngx_slab_page_t *) p; ngx_memzero(pool->pages, pages * sizeof(ngx_slab_page_t)); page = pool->pages; /* only "next" is used in list head */ pool->free.slab = 0; pool->free.next = page; pool->free.prev = 0; page->slab = pages; page->next = &pool->free; page->prev = (uintptr_t) &pool->free; pool->start = ngx_align_ptr(p + pages * sizeof(ngx_slab_page_t), ngx_pagesize); m = pages - (pool->end - pool->start) / ngx_pagesize; if (m > 0) { pages -= m; page->slab = pages; } pool->last = pool->pages + pages; pool->pfree = pages; pool->log_nomem = 1; pool->log_ctx = &pool->zero; pool->zero = '\0'; } void * ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size) { void *p; ngx_shmtx_lock(&pool->mutex); p = ngx_slab_alloc_locked(pool, size); ngx_shmtx_unlock(&pool->mutex); return p; } void * ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size) { size_t s; uintptr_t p, n, m, mask, *bitmap; ngx_uint_t i, slot, shift, map; ngx_slab_page_t *page, *prev, *slots; if (size > ngx_slab_max_size) { ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz", size); page = ngx_slab_alloc_pages(pool, (size >> ngx_pagesize_shift) + ((size % ngx_pagesize) ? 1 : 0)); if (page) { p = ngx_slab_page_addr(pool, page); } else { p = 0; } goto done; } if (size > pool->min_size) { shift = 1; for (s = size - 1; s >>= 1; shift++) { /* void */ } slot = shift - pool->min_shift; } else { shift = pool->min_shift; slot = 0; } pool->stats[slot].reqs++; ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz slot: %ui", size, slot); slots = ngx_slab_slots(pool); page = slots[slot].next; if (page->next != page) { if (shift < ngx_slab_exact_shift) { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page); map = (ngx_pagesize >> shift) / (sizeof(uintptr_t) * 8); for (n = 0; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { for (m = 1, i = 0; m; m <<= 1, i++) { if (bitmap[n] & m) { continue; } bitmap[n] |= m; i = (n * sizeof(uintptr_t) * 8 + i) << shift; p = (uintptr_t) bitmap + i; pool->stats[slot].used++; if (bitmap[n] == NGX_SLAB_BUSY) { for (n = n + 1; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { goto done; } } prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_SMALL; } goto done; } } } } else if (shift == ngx_slab_exact_shift) { for (m = 1, i = 0; m; m <<= 1, i++) { if (page->slab & m) { continue; } page->slab |= m; if (page->slab == NGX_SLAB_BUSY) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_EXACT; } p = ngx_slab_page_addr(pool, page) + (i << shift); pool->stats[slot].used++; goto done; } } else { /* shift > ngx_slab_exact_shift */ mask = ((uintptr_t) 1 << (ngx_pagesize >> shift)) - 1; mask <<= NGX_SLAB_MAP_SHIFT; for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0; m & mask; m <<= 1, i++) { if (page->slab & m) { continue; } page->slab |= m; if ((page->slab & NGX_SLAB_MAP_MASK) == mask) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_BIG; } p = ngx_slab_page_addr(pool, page) + (i << shift); pool->stats[slot].used++; goto done; } } ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_alloc(): page is busy"); ngx_debug_point(); } page = ngx_slab_alloc_pages(pool, 1); if (page) { if (shift < ngx_slab_exact_shift) { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page); n = (ngx_pagesize >> shift) / ((1 << shift) * 8); if (n == 0) { n = 1; } /* "n" elements for bitmap, plus one requested */ bitmap[0] = ((uintptr_t) 2 << n) - 1; map = (ngx_pagesize >> shift) / (sizeof(uintptr_t) * 8); for (i = 1; i < map; i++) { bitmap[i] = 0; } page->slab = shift; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL; slots[slot].next = page; pool->stats[slot].total += (ngx_pagesize >> shift) - n; p = ngx_slab_page_addr(pool, page) + (n << shift); pool->stats[slot].used++; goto done; } else if (shift == ngx_slab_exact_shift) { page->slab = 1; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT; slots[slot].next = page; pool->stats[slot].total += sizeof(uintptr_t) * 8; p = ngx_slab_page_addr(pool, page); pool->stats[slot].used++; goto done; } else { /* shift > ngx_slab_exact_shift */ page->slab = ((uintptr_t) 1 << NGX_SLAB_MAP_SHIFT) | shift; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG; slots[slot].next = page; pool->stats[slot].total += ngx_pagesize >> shift; p = ngx_slab_page_addr(pool, page); pool->stats[slot].used++; goto done; } } p = 0; pool->stats[slot].fails++; done: ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %p", (void *) p); return (void *) p; } void * ngx_slab_calloc(ngx_slab_pool_t *pool, size_t size) { void *p; ngx_shmtx_lock(&pool->mutex); p = ngx_slab_calloc_locked(pool, size); ngx_shmtx_unlock(&pool->mutex); return p; } void * ngx_slab_calloc_locked(ngx_slab_pool_t *pool, size_t size) { void *p; p = ngx_slab_alloc_locked(pool, size); if (p) { ngx_memzero(p, size); } return p; } void ngx_slab_free(ngx_slab_pool_t *pool, void *p) { ngx_shmtx_lock(&pool->mutex); ngx_slab_free_locked(pool, p); ngx_shmtx_unlock(&pool->mutex); } void ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p) { size_t size; uintptr_t slab, m, *bitmap; ngx_uint_t i, n, type, slot, shift, map; ngx_slab_page_t *slots, *page; ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab free: %p", p); if ((u_char *) p < pool->start || (u_char *) p > pool->end) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): outside of pool"); goto fail; } n = ((u_char *) p - pool->start) >> ngx_pagesize_shift; page = &pool->pages[n]; slab = page->slab; type = ngx_slab_page_type(page); switch (type) { case NGX_SLAB_SMALL: shift = slab & NGX_SLAB_SHIFT_MASK; size = (size_t) 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } n = ((uintptr_t) p & (ngx_pagesize - 1)) >> shift; m = (uintptr_t) 1 << (n % (sizeof(uintptr_t) * 8)); n /= sizeof(uintptr_t) * 8; bitmap = (uintptr_t *) ((uintptr_t) p & ~((uintptr_t) ngx_pagesize - 1)); if (bitmap[n] & m) { slot = shift - pool->min_shift; if (page->next == NULL) { slots = ngx_slab_slots(pool); page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL; page->next->prev = (uintptr_t) page | NGX_SLAB_SMALL; } bitmap[n] &= ~m; n = (ngx_pagesize >> shift) / ((1 << shift) * 8); if (n == 0) { n = 1; } if (bitmap[0] & ~(((uintptr_t) 1 << n) - 1)) { goto done; } map = (ngx_pagesize >> shift) / (sizeof(uintptr_t) * 8); for (i = 1; i < map; i++) { if (bitmap[i]) { goto done; } } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= (ngx_pagesize >> shift) - n; goto done; } goto chunk_already_free; case NGX_SLAB_EXACT: m = (uintptr_t) 1 << (((uintptr_t) p & (ngx_pagesize - 1)) >> ngx_slab_exact_shift); size = ngx_slab_exact_size; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } if (slab & m) { slot = ngx_slab_exact_shift - pool->min_shift; if (slab == NGX_SLAB_BUSY) { slots = ngx_slab_slots(pool); page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT; page->next->prev = (uintptr_t) page | NGX_SLAB_EXACT; } page->slab &= ~m; if (page->slab) { goto done; } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= sizeof(uintptr_t) * 8; goto done; } goto chunk_already_free; case NGX_SLAB_BIG: shift = slab & NGX_SLAB_SHIFT_MASK; size = (size_t) 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } m = (uintptr_t) 1 << ((((uintptr_t) p & (ngx_pagesize - 1)) >> shift) + NGX_SLAB_MAP_SHIFT); if (slab & m) { slot = shift - pool->min_shift; if (page->next == NULL) { slots = ngx_slab_slots(pool); page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG; page->next->prev = (uintptr_t) page | NGX_SLAB_BIG; } page->slab &= ~m; if (page->slab & NGX_SLAB_MAP_MASK) { goto done; } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= ngx_pagesize >> shift; goto done; } goto chunk_already_free; case NGX_SLAB_PAGE: if ((uintptr_t) p & (ngx_pagesize - 1)) { goto wrong_chunk; } if (!(slab & NGX_SLAB_PAGE_START)) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): page is already free"); goto fail; } if (slab == NGX_SLAB_PAGE_BUSY) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): pointer to wrong page"); goto fail; } n = ((u_char *) p - pool->start) >> ngx_pagesize_shift; size = slab & ~NGX_SLAB_PAGE_START; ngx_slab_free_pages(pool, &pool->pages[n], size); ngx_slab_junk(p, size << ngx_pagesize_shift); return; } /* not reached */ return; done: pool->stats[slot].used--; ngx_slab_junk(p, size); return; wrong_chunk: ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): pointer to wrong chunk"); goto fail; chunk_already_free: ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): chunk is already free"); fail: return; } static ngx_slab_page_t * ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages) { ngx_slab_page_t *page, *p; for (page = pool->free.next; page != &pool->free; page = page->next) { if (page->slab >= pages) { if (page->slab > pages) { page[page->slab - 1].prev = (uintptr_t) &page[pages]; page[pages].slab = page->slab - pages; page[pages].next = page->next; page[pages].prev = page->prev; p = (ngx_slab_page_t *) page->prev; p->next = &page[pages]; page->next->prev = (uintptr_t) &page[pages]; } else { p = (ngx_slab_page_t *) page->prev; p->next = page->next; page->next->prev = page->prev; } page->slab = pages | NGX_SLAB_PAGE_START; page->next = NULL; page->prev = NGX_SLAB_PAGE; pool->pfree -= pages; if (--pages == 0) { return page; } for (p = page + 1; pages; pages--) { p->slab = NGX_SLAB_PAGE_BUSY; p->next = NULL; p->prev = NGX_SLAB_PAGE; p++; } return page; } } if (pool->log_nomem) { ngx_slab_error(pool, NGX_LOG_CRIT, "ngx_slab_alloc() failed: no memory"); } return NULL; } static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page, ngx_uint_t pages) { ngx_slab_page_t *prev, *join; pool->pfree += pages; page->slab = pages--; if (pages) { ngx_memzero(&page[1], pages * sizeof(ngx_slab_page_t)); } if (page->next) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; } join = page + page->slab; if (join < pool->last) { if (ngx_slab_page_type(join) == NGX_SLAB_PAGE) { if (join->next != NULL) { pages += join->slab; page->slab += join->slab; prev = ngx_slab_page_prev(join); prev->next = join->next; join->next->prev = join->prev; join->slab = NGX_SLAB_PAGE_FREE; join->next = NULL; join->prev = NGX_SLAB_PAGE; } } } if (page > pool->pages) { join = page - 1; if (ngx_slab_page_type(join) == NGX_SLAB_PAGE) { if (join->slab == NGX_SLAB_PAGE_FREE) { join = ngx_slab_page_prev(join); } if (join->next != NULL) { pages += join->slab; join->slab += page->slab; prev = ngx_slab_page_prev(join); prev->next = join->next; join->next->prev = join->prev; page->slab = NGX_SLAB_PAGE_FREE; page->next = NULL; page->prev = NGX_SLAB_PAGE; page = join; } } } if (pages) { page[pages].prev = (uintptr_t) page; } page->prev = (uintptr_t) &pool->free; page->next = pool->free.next; page->next->prev = (uintptr_t) page; pool->free.next = page; } static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text) { ngx_log_error(level, ngx_cycle->log, 0, "%s%s", text, pool->log_ctx); }