From cace7b801d49430522840fa13e9ac2bdc2dcf941 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 4 Jul 2016 13:06:37 +0100 Subject: [PATCH] m25p80: do not put iovec on the stack MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When doing a read-modify-write cycle, QEMU uses the iovec after returning from blk_aio_pwritev. m25p80 puts the iovec on the stack of blk_aio_pwritev's caller, which causes trouble in this case. This has been a problem since commit 243e6f6 ("m25p80: Switch to byte-based block access", 2016-05-12) started doing writes at a smaller granularity than 512 bytes. In principle however it could have broken before when using -drive if=mtd,cache=none on a disk with 4K native sectors. Signed-off-by: Paolo Bonzini Reviewed-by: Cédric Le Goater Reviewed-by: Eric Blake Signed-off-by: Cédric Le Goater Message-id: 1467138270-32481-3-git-send-email-clg@kaod.org Signed-off-by: Peter Maydell --- hw/block/m25p80.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c index 3cdcfce07b..8e4c115735 100644 --- a/hw/block/m25p80.c +++ b/hw/block/m25p80.c @@ -447,6 +447,11 @@ static inline Manufacturer get_man(Flash *s) static void blk_sync_complete(void *opaque, int ret) { + QEMUIOVector *iov = opaque; + + qemu_iovec_destroy(iov); + g_free(iov); + /* do nothing. Masters do not directly interact with the backing store, * only the working copy so no mutexing required. */ @@ -454,31 +459,31 @@ static void blk_sync_complete(void *opaque, int ret) static void flash_sync_page(Flash *s, int page) { - QEMUIOVector iov; + QEMUIOVector *iov = g_new(QEMUIOVector, 1); if (!s->blk || blk_is_read_only(s->blk)) { return; } - qemu_iovec_init(&iov, 1); - qemu_iovec_add(&iov, s->storage + page * s->pi->page_size, + qemu_iovec_init(iov, 1); + qemu_iovec_add(iov, s->storage + page * s->pi->page_size, s->pi->page_size); - blk_aio_pwritev(s->blk, page * s->pi->page_size, &iov, 0, - blk_sync_complete, NULL); + blk_aio_pwritev(s->blk, page * s->pi->page_size, iov, 0, + blk_sync_complete, iov); } static inline void flash_sync_area(Flash *s, int64_t off, int64_t len) { - QEMUIOVector iov; + QEMUIOVector *iov = g_new(QEMUIOVector, 1); if (!s->blk || blk_is_read_only(s->blk)) { return; } assert(!(len % BDRV_SECTOR_SIZE)); - qemu_iovec_init(&iov, 1); - qemu_iovec_add(&iov, s->storage + off, len); - blk_aio_pwritev(s->blk, off, &iov, 0, blk_sync_complete, NULL); + qemu_iovec_init(iov, 1); + qemu_iovec_add(iov, s->storage + off, len); + blk_aio_pwritev(s->blk, off, iov, 0, blk_sync_complete, iov); } static void flash_erase(Flash *s, int offset, FlashCMD cmd)