[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.11] x86/mm: Put the gfn on all paths after get_gfn_query()
commit eb6830a1c8347d0c5e33571f93cbd2d79330798d Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Tue Nov 20 15:32:34 2018 +0100 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Nov 20 15:32:34 2018 +0100 x86/mm: Put the gfn on all paths after get_gfn_query() c/s 7867181b2 "x86/PoD: correctly handle non-order-0 decrease-reservation requests" introduced an early exit in guest_remove_page() for unexpected p2m types. However, get_gfn_query() internally takes the p2m lock, and must be matched with a put_gfn() call later. Fix the erroneous comment beside the declaration of get_gfn_query(). This is XSA-277. Reported-by: Paul Durrant <paul.durrant@xxxxxxxxxx> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> master commit: d80988cfc04ee608bee722448e7c3bc8347ec04c master date: 2018-11-20 14:58:10 +0100 --- xen/common/memory.c | 4 ++++ xen/include/asm-x86/p2m.h | 5 +---- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/xen/common/memory.c b/xen/common/memory.c index 75010b78a5..4fb7962c79 100644 --- a/xen/common/memory.c +++ b/xen/common/memory.c @@ -303,7 +303,11 @@ int guest_remove_page(struct domain *d, unsigned long gmfn) #ifdef CONFIG_X86 mfn = get_gfn_query(d, gmfn, &p2mt); if ( unlikely(p2mt == p2m_invalid) || unlikely(p2mt == p2m_mmio_dm) ) + { + put_gfn(d, gmfn); + return -ENOENT; + } if ( unlikely(p2m_is_paging(p2mt)) ) { diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h index d4b3cfcb6e..3f41deaeea 100644 --- a/xen/include/asm-x86/p2m.h +++ b/xen/include/asm-x86/p2m.h @@ -432,10 +432,7 @@ static inline mfn_t __nonnull(3) get_gfn_type( return get_gfn_type_access(p2m_get_hostp2m(d), gfn, t, &a, q, NULL); } -/* Syntactic sugar: most callers will use one of these. - * N.B. get_gfn_query() is the _only_ one guaranteed not to take the - * p2m lock; none of the others can be called with the p2m or paging - * lock held. */ +/* Syntactic sugar: most callers will use one of these. */ #define get_gfn(d, g, t) get_gfn_type((d), (g), (t), P2M_ALLOC) #define get_gfn_query(d, g, t) get_gfn_type((d), (g), (t), 0) #define get_gfn_unshare(d, g, t) get_gfn_type((d), (g), (t), \ -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.11 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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