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Link: https://lore.kernel.org/r/20210709131537.035851348@linuxfoundation.org
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Fox Chen <foxhlchen@gmail.com>
Tested-by: Shuah Khan <skhan@linuxfoundation.org>
Tested-by: Hulk Robot <hulkrobot@huawei.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Pavel Machek (CIP) <pavel@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 upstream.
In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.
This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6fff7410f6befe5744d54f0418d65a6322998c09 upstream.
Cross-section jumps from .fixup section must be extended.
Signed-off-by: Sid Manning <sidneym@codeaurora.org>
Signed-off-by: Brian Cain <bcain@codeaurora.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f1f99adf05f2138ff2646d756d4674e302e8d02d upstream.
Add the compiler-rt builtins like memcpy to the hexagon kernel.
Signed-off-by: Sid Manning <sidneym@codeaurora.org>
Add SYM_FUNC_START/END, ksyms exports
Signed-off-by: Brian Cain <bcain@codeaurora.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 788dcee0306e1bdbae1a76d1b3478bb899c5838e upstream.
Fix type-o in ptrace.c.
Add missing include: asm/hexagon_vm.h
Remove superfluous cast.
Replace 'p3_0' with 'preds'.
Signed-off-by: Sid Manning <sidneym@codeaurora.org>
Add -mlong-calls to build flags.
Signed-off-by: Brian Cain <bcain@codeaurora.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4ca052b4ea621d0002a5e5feace51f60ad5e6b23 upstream.
Some devices reference an output terminal as the source of extension
units. This is incorrect, as output terminals only have an input pin,
and thus can't be connected to any entity in the forward direction. The
resulting topology would cause issues when registering the media
controller graph. To avoid this problem, connect the extension unit to
the source of the output terminal instead.
While at it, and while no device has been reported to be affected by
this issue, also handle forward scans where two output terminals would
be connected together, and skip the terminals found through such an
invalid connection.
Reported-and-tested-by: John Nealy <jnealy3@yahoo.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 25edcc50d76c834479d11fcc7de46f3da4d95121 upstream.
The Facility Status and Control Register is a privileged SPR that
defines the availability of some features in problem state. Since it
can be written by the guest, we must restore it to the previous host
value after guest exit.
This restoration is currently done by taking the value from
current->thread.fscr, which in the P9 path is not enough anymore
because the guest could context switch the QEMU thread, causing the
guest-current value to be saved into the thread struct.
The above situation manifested when running a QEMU linked against a
libc with System Call Vectored support, which causes scv
instructions to be run by QEMU early during the guest boot (during
SLOF), at which point the FSCR is 0 due to guest entry. After a few
scv calls (1 to a couple hundred), the context switching happens and
the QEMU thread runs with the guest value, resulting in a Facility
Unavailable interrupt.
This patch saves and restores the host value of FSCR in the inner
guest entry loop in a way independent of current->thread.fscr. The old
way of doing it is still kept in place because it works for the old
entry path.
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Cc: Georgy Yakovlev <gyakovlev@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Tested-by: Fox Chen <foxhlchen@gmail.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Shuah Khan <skhan@linuxfoundation.org>
Tested-by: Justin M. Forbes <jforbes@fedoraproject.org>
Tested-by: Pavel Machek (CIP) <pavel@denx.de>
Tested-by: Hulk Robot <hulkrobot@huawei.com>
Tested-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit f71a53d1180d5ecc346f0c6a23191d837fe2871b upstream.
Restore CR4.LA57 to the mmu_role to fix an amusing edge case with nested
virtualization. When KVM (L0) is using TDP, CR4.LA57 is not reflected in
mmu_role.base.level because that tracks the shadow root level, i.e. TDP
level. Normally, this is not an issue because LA57 can't be toggled
while long mode is active, i.e. the guest has to first disable paging,
then toggle LA57, then re-enable paging, thus ensuring an MMU
reinitialization.
But if L1 is crafty, it can load a new CR4 on VM-Exit and toggle LA57
without having to bounce through an unpaged section. L1 can also load a
new CR3 on exit, i.e. it doesn't even need to play crazy paging games, a
single entry PML5 is sufficient. Such shenanigans are only problematic
if L0 and L1 use TDP, otherwise L1 and L2 share an MMU that gets
reinitialized on nested VM-Enter/VM-Exit due to mmu_role.base.guest_mode.
Note, in the L2 case with nested TDP, even though L1 can switch between
L2s with different LA57 settings, thus bypassing the paging requirement,
in that case KVM's nested_mmu will track LA57 in base.level.
This reverts commit 8053f924cad30bf9f9a24e02b6c8ddfabf5202ea.
Fixes: 8053f924cad3 ("KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622175739.3610207-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit edc0b0bccc9c80d9a44d3002dcca94984b25e7cf upstream.
Allow creating FDB steering rules only when in switchdev mode.
The only software model where a userspace application can manipulate
FDB entries is when it manages the eswitch. This is only possible in
switchdev mode where we expose a single RDMA device with representors
for all the vports that are connected to the eswitch.
Fixes: 52438be44112 ("RDMA/mlx5: Allow inserting a steering rule to the FDB")
Link: https://lore.kernel.org/r/e928ae7c58d07f104716a2a8d730963d1bd01204.1623052923.git.leonro@nvidia.com
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
[sudip: use old mlx5_eswitch_mode]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit c6414e1a2bd26b0071e2b9d6034621f705dfd4c0 ]
Both of these drivers use ioport_map(), so they need to
depend on HAS_IOPORT_MAP. Otherwise, they cannot be built
even with COMPILE_TEST on architectures without an ioport
implementation, such as ARCH=um.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d330099115597bbc238d6758a4930e72b49ea9ba ]
AGP for example doesn't have a dma_address array.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210614110517.1624-1-christian.koenig@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3093e6cca3ba7d47848068cb256c489675125181 ]
A disabled/masked interrupt marked as wakeup source must be re-enable
and unmasked in order to be able to wake-up the host. That can be done
by flaging the irqchip with IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND.
Note: It 'sometimes' works without that change, but only thanks to the
lazy generic interrupt disabling (keeping interrupt unmasked).
Reported-by: Michal Koziel <michal.koziel@emlogic.no>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7dd753ca59d6c8cc09aa1ed24f7657524803c7f3 ]
Handle a reported media event code of 3. This indicates that the media has
been removed from the drive and user intervention is required to proceed.
Return DISK_EVENT_EJECT_REQUEST in that case.
Link: https://lore.kernel.org/r/20210611094402.23884-1-limanyi@uniontech.com
Signed-off-by: ManYi Li <limanyi@uniontech.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Tested-by: Fox Chen <foxhlchen@gmail.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Hulk Robot <hulkrobot@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit ebd9c2ae369a45bdd9f8615484db09be58fc242b ]
During boot the Secure Boot Forbidden Signature Database, dbx,
is loaded into the blacklist keyring. Systems booted with shim
have an equivalent Forbidden Signature Database called mokx.
Currently mokx is only used by shim and grub, the contents are
ignored by the kernel.
Add the ability to load mokx into the blacklist keyring during boot.
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
cc: keyrings@vger.kernel.org
Link: https://lore.kernel.org/r/c33c8e3839a41e9654f41cc92c7231104931b1d7.camel@HansenPartnership.com/
Link: https://lore.kernel.org/r/20210122181054.32635-5-eric.snowberg@oracle.com/ # v5
Link: https://lore.kernel.org/r/161428674320.677100.12637282414018170743.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433313205.902181.2502803393898221637.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161529607422.163428.13530426573612578854.stgit@warthog.procyon.org.uk/ # v3
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d1f044103dad70c1cec0a8f3abdf00834fec8b98 ]
Add a new Kconfig option called SYSTEM_REVOCATION_KEYS. If set,
this option should be the filename of a PEM-formated file containing
X.509 certificates to be included in the default blacklist keyring.
DH Changes:
- Make the new Kconfig option depend on SYSTEM_REVOCATION_LIST.
- Fix SYSTEM_REVOCATION_KEYS=n, but CONFIG_SYSTEM_REVOCATION_LIST=y[1][2].
- Use CONFIG_SYSTEM_REVOCATION_LIST for extract-cert[3].
- Use CONFIG_SYSTEM_REVOCATION_LIST for revocation_certificates.o[3].
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Randy Dunlap <rdunlap@infradead.org>
cc: keyrings@vger.kernel.org
Link: https://lore.kernel.org/r/e1c15c74-82ce-3a69-44de-a33af9b320ea@infradead.org/ [1]
Link: https://lore.kernel.org/r/20210303034418.106762-1-eric.snowberg@oracle.com/ [2]
Link: https://lore.kernel.org/r/20210304175030.184131-1-eric.snowberg@oracle.com/ [3]
Link: https://lore.kernel.org/r/20200930201508.35113-3-eric.snowberg@oracle.com/
Link: https://lore.kernel.org/r/20210122181054.32635-4-eric.snowberg@oracle.com/ # v5
Link: https://lore.kernel.org/r/161428673564.677100.4112098280028451629.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433312452.902181.4146169951896577982.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161529606657.163428.3340689182456495390.stgit@warthog.procyon.org.uk/ # v3
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 2565ca7f5ec1a98d51eea8860c4ab923f1ca2c85 ]
Move functionality within load_system_certificate_list to a common
function, so it can be reused in the future.
DH Changes:
- Added inclusion of common.h to common.c (Eric [1]).
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: keyrings@vger.kernel.org
Link: https://lore.kernel.org/r/EDA280F9-F72D-4181-93C7-CDBE95976FF7@oracle.com/ [1]
Link: https://lore.kernel.org/r/20200930201508.35113-2-eric.snowberg@oracle.com/
Link: https://lore.kernel.org/r/20210122181054.32635-3-eric.snowberg@oracle.com/ # v5
Link: https://lore.kernel.org/r/161428672825.677100.7545516389752262918.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433311696.902181.3599366124784670368.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161529605850.163428.7786675680201528556.stgit@warthog.procyon.org.uk/ # v3
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 56c5812623f95313f6a46fbf0beee7fa17c68bbf ]
This fixes CVE-2020-26541.
The Secure Boot Forbidden Signature Database, dbx, contains a list of now
revoked signatures and keys previously approved to boot with UEFI Secure
Boot enabled. The dbx is capable of containing any number of
EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID
entries.
Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are
skipped.
Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID
is found, it is added as an asymmetrical key to the .blacklist keyring.
Anytime the .platform keyring is used, the keys in the .blacklist keyring
are referenced, if a matching key is found, the key will be rejected.
[DH: Made the following changes:
- Added to have a config option to enable the facility. This allows a
Kconfig solution to make sure that pkcs7_validate_trust() is
enabled.[1][2]
- Moved the functions out from the middle of the blacklist functions.
- Added kerneldoc comments.]
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
cc: Randy Dunlap <rdunlap@infradead.org>
cc: Mickaël Salaün <mic@digikod.net>
cc: Arnd Bergmann <arnd@kernel.org>
cc: keyrings@vger.kernel.org
Link: https://lore.kernel.org/r/20200901165143.10295-1-eric.snowberg@oracle.com/ # rfc
Link: https://lore.kernel.org/r/20200909172736.73003-1-eric.snowberg@oracle.com/ # v2
Link: https://lore.kernel.org/r/20200911182230.62266-1-eric.snowberg@oracle.com/ # v3
Link: https://lore.kernel.org/r/20200916004927.64276-1-eric.snowberg@oracle.com/ # v4
Link: https://lore.kernel.org/r/20210122181054.32635-2-eric.snowberg@oracle.com/ # v5
Link: https://lore.kernel.org/r/161428672051.677100.11064981943343605138.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433310942.902181.4901864302675874242.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161529605075.163428.14625520893961300757.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/bc2c24e3-ed68-2521-0bf4-a1f6be4a895d@infradead.org/ [1]
Link: https://lore.kernel.org/r/20210225125638.1841436-1-arnd@kernel.org/ [2]
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit f54b3ca7ea1e5e02f481cf4ca54568e57bd66086 upstream.
This reverts commit 1815d9c86e3090477fbde066ff314a7e9721ee0f.
Unfortunately this inverts the locking hierarchy, so back to the
drawing board. Full lockdep splat below:
======================================================
WARNING: possible circular locking dependency detected
5.13.0-rc7-CI-CI_DRM_10254+ #1 Not tainted
------------------------------------------------------
kms_frontbuffer/1087 is trying to acquire lock:
ffff88810dcd01a8 (&dev->master_mutex){+.+.}-{3:3}, at: drm_is_current_master+0x1b/0x40
but task is already holding lock:
ffff88810dcd0488 (&dev->mode_config.mutex){+.+.}-{3:3}, at: drm_mode_getconnector+0x1c6/0x4a0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&dev->mode_config.mutex){+.+.}-{3:3}:
__mutex_lock+0xab/0x970
drm_client_modeset_probe+0x22e/0xca0
__drm_fb_helper_initial_config_and_unlock+0x42/0x540
intel_fbdev_initial_config+0xf/0x20 [i915]
async_run_entry_fn+0x28/0x130
process_one_work+0x26d/0x5c0
worker_thread+0x37/0x380
kthread+0x144/0x170
ret_from_fork+0x1f/0x30
-> #1 (&client->modeset_mutex){+.+.}-{3:3}:
__mutex_lock+0xab/0x970
drm_client_modeset_commit_locked+0x1c/0x180
drm_client_modeset_commit+0x1c/0x40
__drm_fb_helper_restore_fbdev_mode_unlocked+0x88/0xb0
drm_fb_helper_set_par+0x34/0x40
intel_fbdev_set_par+0x11/0x40 [i915]
fbcon_init+0x270/0x4f0
visual_init+0xc6/0x130
do_bind_con_driver+0x1e5/0x2d0
do_take_over_console+0x10e/0x180
do_fbcon_takeover+0x53/0xb0
register_framebuffer+0x22d/0x310
__drm_fb_helper_initial_config_and_unlock+0x36c/0x540
intel_fbdev_initial_config+0xf/0x20 [i915]
async_run_entry_fn+0x28/0x130
process_one_work+0x26d/0x5c0
worker_thread+0x37/0x380
kthread+0x144/0x170
ret_from_fork+0x1f/0x30
-> #0 (&dev->master_mutex){+.+.}-{3:3}:
__lock_acquire+0x151e/0x2590
lock_acquire+0xd1/0x3d0
__mutex_lock+0xab/0x970
drm_is_current_master+0x1b/0x40
drm_mode_getconnector+0x37e/0x4a0
drm_ioctl_kernel+0xa8/0xf0
drm_ioctl+0x1e8/0x390
__x64_sys_ioctl+0x6a/0xa0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of: &dev->master_mutex --> &client->modeset_mutex --> &dev->mode_config.mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&dev->mode_config.mutex);
lock(&client->modeset_mutex);
lock(&dev->mode_config.mutex);
lock(&dev->master_mutex);
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commit 827a746f405d25f79560c7868474aec5aee174e1 upstream.
It's not sufficient to skip reading when the pos is beyond the EOF.
There may be data at the head of the page that we need to fill in
before the write.
Add a new helper function that corrects and clarifies the logic of
when we can skip reads, and have it only zero out the part of the page
that won't have data copied in for the write.
Finally, don't set the page Uptodate after zeroing. It's not up to date
since the write data won't have been copied in yet.
[DH made the following changes:
- Prefixed the new function with "netfs_".
- Don't call zero_user_segments() for a full-page write.
- Altered the beyond-last-page check to avoid a DIV instruction and got
rid of then-redundant zero-length file check.
]
[ Note: this fix is commit 827a746f405d in mainline kernels. The
original bug was in ceph, but got lifted into the fs/netfs
library for v5.13. This backport should apply to stable
kernels v5.10 though v5.12. ]
Fixes: e1b1240c1ff5f ("netfs: Add write_begin helper")
Reported-by: Andrew W Elble <aweits@rit.edu>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: ceph-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20210613233345.113565-1-jlayton@kernel.org/
Link: https://lore.kernel.org/r/162367683365.460125.4467036947364047314.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/162391826758.1173366.11794946719301590013.stgit@warthog.procyon.org.uk/ # v2
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5f89468e2f060031cd89fd4287298e0eaf246bf6 upstream.
in case of driver wants to sync part of ranges with offset,
swiotlb_tbl_sync_single() copies from orig_addr base to tlb_addr with
offset and ends up with data mismatch.
It was removed from
"swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single",
but said logic has to be added back in.
From Linus's email:
"That commit which the removed the offset calculation entirely, because the old
(unsigned long)tlb_addr & (IO_TLB_SIZE - 1)
was wrong, but instead of removing it, I think it should have just
fixed it to be
(tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
instead. That way the slot offset always matches the slot index calculation."
(Unfortunatly that broke NVMe).
The use-case that drivers are hitting is as follow:
1. Get dma_addr_t from dma_map_single()
dma_addr_t tlb_addr = dma_map_single(dev, vaddr, vsize, DMA_TO_DEVICE);
|<---------------vsize------------->|
+-----------------------------------+
| | original buffer
+-----------------------------------+
vaddr
swiotlb_align_offset
|<----->|<---------------vsize------------->|
+-------+-----------------------------------+
| | | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
2. Do something
3. Sync dma_addr_t through dma_sync_single_for_device(..)
dma_sync_single_for_device(dev, tlb_addr + offset, size, DMA_TO_DEVICE);
Error case.
Copy data to original buffer but it is from base addr (instead of
base addr + offset) in original buffer:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- size ->|
+-----------------------------------+
|##########| | original buffer
+-----------------------------------+
vaddr
The fix is to copy the data to the original buffer and take into
account the offset, like so:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- offset ->|<- size ->|
+-----------------------------------+
| |##########| | original buffer
+-----------------------------------+
vaddr
[One fix which was Linus's that made more sense to as it created a
symmetry would break NVMe. The reason for that is the:
unsigned int offset = (tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
would come up with the proper offset, but it would lose the
alignment (which this patch contains).]
Fixes: 16fc3cef33a0 ("swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single")
Signed-off-by: Bumyong Lee <bumyong.lee@samsung.com>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reported-by: Dominique MARTINET <dominique.martinet@atmark-techno.com>
Reported-by: Horia Geantă <horia.geanta@nxp.com>
Tested-by: Horia Geantă <horia.geanta@nxp.com>
CC: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 934002cd660b035b926438244b4294e647507e13 upstream.
Send SEV_CMD_DECOMMISSION command to PSP firmware if ASID binding
fails. If a failure happens after a successful LAUNCH_START command,
a decommission command should be executed. Otherwise, guest context
will be unfreed inside the AMD SP. After the firmware will not have
memory to allocate more SEV guest context, LAUNCH_START command will
begin to fail with SEV_RET_RESOURCE_LIMIT error.
The existing code calls decommission inside sev_unbind_asid, but it is
not called if a failure happens before guest activation succeeds. If
sev_bind_asid fails, decommission is never called. PSP firmware has a
limit for the number of guests. If sev_asid_binding fails many times,
PSP firmware will not have resources to create another guest context.
Cc: stable@vger.kernel.org
Fixes: 59414c989220 ("KVM: SVM: Add support for KVM_SEV_LAUNCH_START command")
Reported-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Alper Gun <alpergun@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210610174604.2554090-1-alpergun@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit fe19bd3dae3d15d2fbfdb3de8839a6ea0fe94264 upstream.
If more than one futex is placed on a shmem huge page, it can happen
that waking the second wakes the first instead, and leaves the second
waiting: the key's shared.pgoff is wrong.
When 3.11 commit 13d60f4b6ab5 ("futex: Take hugepages into account when
generating futex_key"), the only shared huge pages came from hugetlbfs,
and the code added to deal with its exceptional page->index was put into
hugetlb source. Then that was missed when 4.8 added shmem huge pages.
page_to_pgoff() is what others use for this nowadays: except that, as
currently written, it gives the right answer on hugetlbfs head, but
nonsense on hugetlbfs tails. Fix that by calling hugetlbfs-specific
hugetlb_basepage_index() on PageHuge tails as well as on head.
Yes, it's unconventional to declare hugetlb_basepage_index() there in
pagemap.h, rather than in hugetlb.h; but I do not expect anything but
page_to_pgoff() ever to need it.
[akpm@linux-foundation.org: give hugetlb_basepage_index() prototype the correct scope]
Link: https://lkml.kernel.org/r/b17d946b-d09-326e-b42a-52884c36df32@google.com
Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
Reported-by: Neel Natu <neelnatu@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Zhang Yi <wetpzy@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a7a69d8ba88d8dcee7ef00e91d413a4bd003a814 upstream.
Aha! Shouldn't that quick scan over pte_none()s make sure that it holds
ptlock in the PVMW_SYNC case? That too might have been responsible for
BUGs or WARNs in split_huge_page_to_list() or its unmap_page(), though
I've never seen any.
Link: https://lkml.kernel.org/r/1bdf384c-8137-a149-2a1e-475a4791c3c@google.com
Link: https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Wang Yugui <wangyugui@e16-tech.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a9a7504d9beaf395481faa91e70e2fd08f7a3dde upstream.
Running certain tests with a DEBUG_VM kernel would crash within hours,
on the total_mapcount BUG() in split_huge_page_to_list(), while trying
to free up some memory by punching a hole in a shmem huge page: split's
try_to_unmap() was unable to find all the mappings of the page (which,
on a !DEBUG_VM kernel, would then keep the huge page pinned in memory).
Crash dumps showed two tail pages of a shmem huge page remained mapped
by pte: ptes in a non-huge-aligned vma of a gVisor process, at the end
of a long unmapped range; and no page table had yet been allocated for
the head of the huge page to be mapped into.
Although designed to handle these odd misaligned huge-page-mapped-by-pte
cases, page_vma_mapped_walk() falls short by returning false prematurely
when !pmd_present or !pud_present or !p4d_present or !pgd_present: there
are cases when a huge page may span the boundary, with ptes present in
the next.
Restructure page_vma_mapped_walk() as a loop to continue in these cases,
while keeping its layout much as before. Add a step_forward() helper to
advance pvmw->address across those boundaries: originally I tried to use
mm's standard p?d_addr_end() macros, but hit the same crash 512 times
less often: because of the way redundant levels are folded together, but
folded differently in different configurations, it was just too
difficult to use them correctly; and step_forward() is simpler anyway.
Link: https://lkml.kernel.org/r/fedb8632-1798-de42-f39e-873551d5bc81@google.com
Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a765c417d876cc635f628365ec9aa6f09470069a upstream.
page_vma_mapped_walk() cleanup: get THP's vma_address_end() at the
start, rather than later at next_pte.
It's a little unnecessary overhead on the first call, but makes for a
simpler loop in the following commit.
Link: https://lkml.kernel.org/r/4542b34d-862f-7cb4-bb22-e0df6ce830a2@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 474466301dfd8b39a10c01db740645f3f7ae9a28 upstream.
page_vma_mapped_walk() cleanup: add a label this_pte, matching next_pte,
and use "goto this_pte", in place of the "while (1)" loop at the end.
Link: https://lkml.kernel.org/r/a52b234a-851-3616-2525-f42736e8934@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b3807a91aca7d21c05d5790612e49969117a72b9 upstream.
page_vma_mapped_walk() cleanup: add a level of indentation to much of
the body, making no functional change in this commit, but reducing the
later diff when this is all converted to a loop.
[hughd@google.com: : page_vma_mapped_walk(): add a level of indentation fix]
Link: https://lkml.kernel.org/r/7f817555-3ce1-c785-e438-87d8efdcaf26@google.com
Link: https://lkml.kernel.org/r/efde211-f3e2-fe54-977-ef481419e7f3@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 448282487483d6fa5b2eeeafaa0acc681e544a9c upstream.
page_vma_mapped_walk() cleanup: adjust the test for crossing page table
boundary - I believe pvmw->address is always page-aligned, but nothing
else here assumed that; and remember to reset pvmw->pte to NULL after
unmapping the page table, though I never saw any bug from that.
Link: https://lkml.kernel.org/r/799b3f9c-2a9e-dfef-5d89-26e9f76fd97@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e2e1d4076c77b3671cf8ce702535ae7dee3acf89 upstream.
page_vma_mapped_walk() cleanup: rearrange the !pmd_present() block to
follow the same "return not_found, return not_found, return true"
pattern as the block above it (note: returning not_found there is never
premature, since existence or prior existence of huge pmd guarantees
good alignment).
Link: https://lkml.kernel.org/r/378c8650-1488-2edf-9647-32a53cf2e21@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3306d3119ceacc43ea8b141a73e21fea68eec30c upstream.
page_vma_mapped_walk() cleanup: re-evaluate pmde after taking lock, then
use it in subsequent tests, instead of repeatedly dereferencing pointer.
Link: https://lkml.kernel.org/r/53fbc9d-891e-46b2-cb4b-468c3b19238e@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6d0fd5987657cb0c9756ce684e3a74c0f6351728 upstream.
page_vma_mapped_walk() cleanup: get the hugetlbfs PageHuge case out of
the way at the start, so no need to worry about it later.
Link: https://lkml.kernel.org/r/e31a483c-6d73-a6bb-26c5-43c3b880a2@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f003c03bd29e6f46fef1b9a8e8d636ac732286d5 upstream.
Patch series "mm: page_vma_mapped_walk() cleanup and THP fixes".
I've marked all of these for stable: many are merely cleanups, but I
think they are much better before the main fix than after.
This patch (of 11):
page_vma_mapped_walk() cleanup: sometimes the local copy of pvwm->page
was used, sometimes pvmw->page itself: use the local copy "page"
throughout.
Link: https://lkml.kernel.org/r/589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com
Link: https://lkml.kernel.org/r/88e67645-f467-c279-bf5e-af4b5c6b13eb@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 504e070dc08f757bccaed6d05c0f53ecbfac8a23 ]
When debugging the bug reported by Wang Yugui [1], try_to_unmap() may
fail, but the first VM_BUG_ON_PAGE() just checks page_mapcount() however
it may miss the failure when head page is unmapped but other subpage is
mapped. Then the second DEBUG_VM BUG() that check total mapcount would
catch it. This may incur some confusion.
As this is not a fatal issue, so consolidate the two DEBUG_VM checks
into one VM_WARN_ON_ONCE_PAGE().
[1] https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
Link: https://lkml.kernel.org/r/d0f0db68-98b8-ebfb-16dc-f29df24cf012@google.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jue Wang <juew@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Note on stable backport: fixed up variables in split_huge_page_to_list().
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 22061a1ffabdb9c3385de159c5db7aac3a4df1cc ]
There is a race between THP unmapping and truncation, when truncate sees
pmd_none() and skips the entry, after munmap's zap_huge_pmd() cleared
it, but before its page_remove_rmap() gets to decrement
compound_mapcount: generating false "BUG: Bad page cache" reports that
the page is still mapped when deleted. This commit fixes that, but not
in the way I hoped.
The first attempt used try_to_unmap(page, TTU_SYNC|TTU_IGNORE_MLOCK)
instead of unmap_mapping_range() in truncate_cleanup_page(): it has
often been an annoyance that we usually call unmap_mapping_range() with
no pages locked, but there apply it to a single locked page.
try_to_unmap() looks more suitable for a single locked page.
However, try_to_unmap_one() contains a VM_BUG_ON_PAGE(!pvmw.pte,page):
it is used to insert THP migration entries, but not used to unmap THPs.
Copy zap_huge_pmd() and add THP handling now? Perhaps, but their TLB
needs are different, I'm too ignorant of the DAX cases, and couldn't
decide how far to go for anon+swap. Set that aside.
The second attempt took a different tack: make no change in truncate.c,
but modify zap_huge_pmd() to insert an invalidated huge pmd instead of
clearing it initially, then pmd_clear() between page_remove_rmap() and
unlocking at the end. Nice. But powerpc blows that approach out of the
water, with its serialize_against_pte_lookup(), and interesting pgtable
usage. It would need serious help to get working on powerpc (with a
minor optimization issue on s390 too). Set that aside.
Just add an "if (page_mapped(page)) synchronize_rcu();" or other such
delay, after unmapping in truncate_cleanup_page()? Perhaps, but though
that's likely to reduce or eliminate the number of incidents, it would
give less assurance of whether we had identified the problem correctly.
This successful iteration introduces "unmap_mapping_page(page)" instead
of try_to_unmap(), and goes the usual unmap_mapping_range_tree() route,
with an addition to details. Then zap_pmd_range() watches for this
case, and does spin_unlock(pmd_lock) if so - just like
page_vma_mapped_walk() now does in the PVMW_SYNC case. Not pretty, but
safe.
Note that unmap_mapping_page() is doing a VM_BUG_ON(!PageLocked) to
assert its interface; but currently that's only used to make sure that
page->mapping is stable, and zap_pmd_range() doesn't care if the page is
locked or not. Along these lines, in invalidate_inode_pages2_range()
move the initial unmap_mapping_ |
