In ecbfb9f118bce4 ("dm raid: add raid level takeover support") a new
compatible feature flag was added. Validation for these compat_features
was added but this only passes for new raid mappings with this feature
flag. This causes previously created raid mappings to be failed at
import.
Check compat_features for the only valid combination.
On an AWS t2.micro instance (Xeon E5-2670, 991MiB of memory).
Occasionally (about once a day), kswapd0 falls into a busy loop and
spins on 100% CPU usage indefinitely. Reject to do the zone balance
when the memory is too small.
Debugging a data corruption issue with virtio-net/vhost-net led to
the observation that __copy_tofrom_user was occasionally returning
a value 16 larger than it should. Since the return value from
__copy_tofrom_user is the number of bytes not copied, this means
that __copy_tofrom_user can occasionally return a value larger
than the number of bytes it was asked to copy. In turn this can
cause higher-level copy functions such as copy_page_to_iter_iovec
to corrupt memory by copying data into the wrong memory locations.
It turns out that the failing case involves a fault on the store
at label 79, and at that point the first unmodified byte of the
destination is at R3 + 16. Consequently the exception handler
for that store needs to add 16 to R3 before using it to work out
how many bytes were not copied, but in this one case it was not
adding the offset to R3. To fix it, this moves the label 179 to
the point where we add 16 to R3. I have checked manually all the
exception handlers for the loads and stores in this code and the
rest of them are correct (it would be excellent to have an
automated test of all the exception cases).
This commit fixes a stack corruption in the pseries specific code dealing
with the huge pages.
In __pSeries_lpar_hugepage_invalidate() the buffer used to pass arguments
to the hypervisor is not large enough. This leads to a stack corruption
where a previously saved register could be corrupted leading to unexpected
result in the caller, like the following panic:
Most of the time, the bug is surfacing in a caller up in the stack from
__pSeries_lpar_hugepage_invalidate() which is quite confusing.
This bug is pending since v3.11 but was hidden if a caller of the
caller of __pSeries_lpar_hugepage_invalidate() has pushed the corruped
register (r18 in this case) in the stack and is not using it until
restoring it. GCC 6.2.0 seems to raise it more frequently.
This commit also change the definition of the parameter buffer in
pSeries_lpar_flush_hash_range() to rely on the global define
PLPAR_HCALL9_BUFSIZE (no functional change here).
If a VFC port gets unmapped in the VIOS, it may not respond with a CRQ
init complete following H_REG_CRQ. If this occurs, we can end up having
called scsi_block_requests and not a resulting unblock until the init
complete happens, which may never occur, and we end up hanging I/O
requests. This patch ensures the host action stay set to
IBMVFC_HOST_ACTION_TGT_DEL so we move all rports into devloss state and
unblock unless we receive an init complete.
Cc: <email address hidden>
Signed-off-by: Brian King <email address hidden>
Acked-by: Tyrel Datwyler <email address hidden>
Signed-off-by: Martin K. Petersen <email address hidden>
(cherry picked from linux-next commit 07d0e9a847401ffd2f09bd450d41644cd090e81d)
Signed-off-by: Tim Gardner <email address hidden>
Acked-by: Seth Forshee <email address hidden>
Acked-by: Leann Ogasawara <email address hidden>
Signed-off-by: Seth Forshee <email address hidden>
