Date: Thu, 05 Mar 2026 11:13:23 +0000 From: Zhenlei Huang <zlei@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: ec22c4022ddb - stable/13 - vnet: Ensure the space allocated by vnet_data_alloc() is sufficent aligned Message-ID: <69a96553.40486.7911acc4@gitrepo.freebsd.org>
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The branch stable/13 has been updated by zlei: URL: https://cgit.FreeBSD.org/src/commit/?id=ec22c4022ddbc62be17b2bc65fe8b6113c8d76e7 commit ec22c4022ddbc62be17b2bc65fe8b6113c8d76e7 Author: Zhenlei Huang <zlei@FreeBSD.org> AuthorDate: 2026-02-28 11:35:42 +0000 Commit: Zhenlei Huang <zlei@FreeBSD.org> CommitDate: 2026-03-05 11:12:41 +0000 vnet: Ensure the space allocated by vnet_data_alloc() is sufficent aligned Some 32-bit architectures, e.g., armv7, require strict 8-byte alignment while doing atomic 64-bit access. Hence aligning to the pointer type (4-byte alignment) does not meet the requirement on those architectures. Make the space allocated by vnet_data_alloc() sufficent aligned to avoid unaligned access. PR: 265639 Diagnosed by: markj Reviewed by: jhb, markj Co-authored-by: jhb MFC after: 5 days Differential Revision: https://reviews.freebsd.org/D55560 (cherry picked from commit 32beb3ae71cb320dbe4190a01c036943d99083b3) (cherry picked from commit 973d607b284ba68e63f0386af44c28bfde15add2) (cherry picked from commit baee504b868b9417c815c0de6474a0d6e5d6b4ac) --- sys/net/vnet.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/sys/net/vnet.c b/sys/net/vnet.c index da5fc5b52a72..a55fd49cb5da 100644 --- a/sys/net/vnet.c +++ b/sys/net/vnet.c @@ -172,11 +172,17 @@ static MALLOC_DEFINE(M_VNET_DATA, "vnet_data", "VNET data"); #define VNET_MODMIN (8 * PAGE_SIZE) #define VNET_SIZE roundup2(VNET_BYTES, PAGE_SIZE) +/* + * Ensure space allocated by vnet_data_alloc() is suitably aligned for any + * object. + */ +#define VNET_DATAALIGN _Alignof(__max_align_t) + /* * Space to store virtualized global variables from loadable kernel modules, * and the free list to manage it. */ -VNET_DEFINE_STATIC(char, modspace[VNET_MODMIN] __aligned(__alignof(void *))); +VNET_DEFINE_STATIC(char, modspace[VNET_MODMIN] __aligned(VNET_DATAALIGN)); /* * Global lists of subsystem constructor and destructors for vnets. They are @@ -381,7 +387,7 @@ vnet_data_alloc(int size) void *s; s = NULL; - size = roundup2(size, sizeof(void *)); + size = roundup2(size, VNET_DATAALIGN); sx_xlock(&vnet_data_free_lock); TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) { if (df->vnd_len < size) @@ -399,6 +405,8 @@ vnet_data_alloc(int size) } sx_xunlock(&vnet_data_free_lock); + KASSERT(((uintptr_t)s & (VNET_DATAALIGN - 1)) == 0, + ("unaligned vnet alloc %p", s)); return (s); } @@ -413,7 +421,7 @@ vnet_data_free(void *start_arg, int size) uintptr_t start; uintptr_t end; - size = roundup2(size, sizeof(void *)); + size = roundup2(size, VNET_DATAALIGN); start = (uintptr_t)start_arg; end = start + size; /*home | help
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