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authorPratyush Yadav <pratyush@kernel.org>2025-11-03 19:02:32 +0100
committerAndrew Morton <akpm@linux-foundation.org>2025-11-09 21:19:47 -0800
commitb05addf6f0596edb1f82ab4059438c7ef2d2686d (patch)
tree8abae364a9020a22cdf18d146d5e5e93f0549f2c
parent7ecd2e439d1272ac02d798b0033a426e3b00dff5 (diff)
kho: warn and exit when unpreserved page wasn't preserved
Calling __kho_unpreserve() on a pair of (pfn, end_pfn) that wasn't preserved is a bug. Currently, if that is done, the physxa or bits can be NULL. This results in a soft lockup since a NULL physxa or bits results in redoing the loop without ever making any progress. Return when physxa or bits are not found, but WARN first to loudly indicate invalid behaviour. Link: https://lkml.kernel.org/r/20251103180235.71409-3-pratyush@kernel.org Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") Signed-off-by: Pratyush Yadav <pratyush@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Baoquan He <bhe@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--kernel/kexec_handover.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index e0bafe7c0ded..03d12e27189f 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -171,12 +171,12 @@ static void __kho_unpreserve(struct kho_mem_track *track, unsigned long pfn,
const unsigned long pfn_high = pfn >> order;
physxa = xa_load(&track->orders, order);
- if (!physxa)
- continue;
+ if (WARN_ON_ONCE(!physxa))
+ return;
bits = xa_load(&physxa->phys_bits, pfn_high / PRESERVE_BITS);
- if (!bits)
- continue;
+ if (WARN_ON_ONCE(!bits))
+ return;
clear_bit(pfn_high % PRESERVE_BITS, bits->preserve);