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| author | Heiko Carstens <hca@linux.ibm.com> | 2026-07-20 10:58:31 +0200 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2026-07-30 00:29:10 +0200 |
| commit | ecb00aa6fb7f473136fb2e496ad91116a568fc7f (patch) | |
| tree | cd7d28b4694b00c530fd444a785dfd0eb381865a | |
| parent | a2e5a9d853e015bc876399eb18435aa88101c60a (diff) | |
| download | linux-next-ecb00aa6fb7f473136fb2e496ad91116a568fc7f.tar.gz linux-next-ecb00aa6fb7f473136fb2e496ad91116a568fc7f.zip | |
s390/mm: Remove folio handling for kernel faults in do_secure_storage_access()
Remove folio handling for secure storage access exceptions that happen
via the kernel mapping. Using folio_try_get() for exceptions via the
kernel mapping is racy: for example such an exception may happen on one
CPU, while a different CPU frees the corresponding page. Subsequently the
page can be part of a folio of different size, before the faulting CPU
executes folio_try_get(). This may lead to data corruption.
As of now this scenario does not seem to be possible, however with the
upcoming load_unaligned_zeropad() this is possible.
As a side effect PG_arch_1 is not cleared anymore for such faults via the
kernel mapping. However given that this bit is over-indicating it
shouldn't matter.
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
| -rw-r--r-- | arch/s390/mm/fault.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index e650cdfa2523..776549d55c94 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -440,13 +440,7 @@ void do_secure_storage_access(struct pt_regs *regs) if (is_kernel_fault(regs)) { if (is_vmalloc_addr((void *)addr)) return handle_fault_error_nolock(regs, 0); - folio = virt_to_folio((void *)addr); - if (unlikely(!folio_try_get(folio))) - return; - rc = uv_convert_from_secure(folio_to_phys(folio)); - if (!rc) - clear_bit(PG_arch_1, &folio->flags.f); - folio_put(folio); + rc = uv_convert_from_secure(__pa(addr)); /* * There are some valid fixup types for kernel * accesses to donated secure memory. zeropad is one |