diff options
| author | Zhenlei Huang <zlei@FreeBSD.org> | 2026-02-28 11:35:42 +0000 |
|---|---|---|
| committer | Zhenlei Huang <zlei@FreeBSD.org> | 2026-02-28 11:35:42 +0000 |
| commit | 32beb3ae71cb320dbe4190a01c036943d99083b3 (patch) | |
| tree | b4a9e8a84cda8f24d1b24bed985042fac28a5bc5 | |
| parent | d44d79e577eab3e66b993c783b969b82678792d1 (diff) | |
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
| -rw-r--r-- | sys/net/vnet.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/sys/net/vnet.c b/sys/net/vnet.c index a2b827052dd3..5ef68d11227a 100644 --- a/sys/net/vnet.c +++ b/sys/net/vnet.c @@ -172,10 +172,16 @@ static MALLOC_DEFINE(M_VNET_DATA, "vnet_data", "VNET data"); #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)); /* * A copy of the initial values of all virtualized global variables. @@ -385,7 +391,7 @@ 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) @@ -403,6 +409,8 @@ 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); } @@ -417,7 +425,7 @@ 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; /* |