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| author | alc <alc@FreeBSD.org> | 2004-09-29 19:20:40 +0000 |
|---|---|---|
| committer | alc <alc@FreeBSD.org> | 2004-09-29 19:20:40 +0000 |
| commit | 118a3c283b4d55527625f7c225bab927cc6e8a5b (patch) | |
| tree | 84e879c73d19a080f90e5a8d82f490bd13e57a88 /sys/amd64/include | |
| parent | 3793e610ff87a0e982b946fb512883efc2a352a3 (diff) | |
| download | FreeBSD-src-118a3c283b4d55527625f7c225bab927cc6e8a5b.zip FreeBSD-src-118a3c283b4d55527625f7c225bab927cc6e8a5b.tar.gz | |
Prevent the unexpected deallocation of a page table page while performing
pmap_copy(). This entails additional locking in pmap_copy() and the
addition of a "flags" parameter to the page table page allocator for
specifying whether it may sleep when memory is unavailable. (Already,
pmap_copy() checks the availability of memory, aborting if it is scarce.
In theory, another CPU could, however, allocate memory between
pmap_copy()'s check and the call to the page table page allocator,
causing the current thread to release its locks and sleep. This change
makes this scenario impossible.)
Reviewed by: tegge@
Diffstat (limited to 'sys/amd64/include')
| -rw-r--r-- | sys/amd64/include/pmap.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sys/amd64/include/pmap.h b/sys/amd64/include/pmap.h index 3640e2f..90da462 100644 --- a/sys/amd64/include/pmap.h +++ b/sys/amd64/include/pmap.h @@ -240,7 +240,7 @@ extern struct pmap kernel_pmap_store; mtx_assert(&(pmap)->pm_mtx, (type)) #define PMAP_LOCK_DESTROY(pmap) mtx_destroy(&(pmap)->pm_mtx) #define PMAP_LOCK_INIT(pmap) mtx_init(&(pmap)->pm_mtx, "pmap", \ - NULL, MTX_DEF) + NULL, MTX_DEF | MTX_DUPOK) #define PMAP_LOCKED(pmap) mtx_owned(&(pmap)->pm_mtx) #define PMAP_MTX(pmap) (&(pmap)->pm_mtx) #define PMAP_TRYLOCK(pmap) mtx_trylock(&(pmap)->pm_mtx) |
