commit 2f3389c738 upstream.
Driver allocates the LL2 rx buffers from kmalloc()
area to construct the skb using slab_build_skb()
The required size allocation seems to have overlooked
for accounting both skb_shared_info size and device
placement padding bytes which results into the below
panic when doing skb_put() for a standard MTU sized frame.
skbuff: skb_over_panic: text:ffffffffc0b0225f len:1514 put:1514
head:ff3dabceaf39c000 data:ff3dabceaf39c042 tail:0x62c end:0x566
dev:<NULL>
…
skb_panic+0x48/0x4a
skb_put.cold+0x10/0x10
qed_ll2b_complete_rx_packet+0x14f/0x260 [qed]
qed_ll2_rxq_handle_completion.constprop.0+0x169/0x200 [qed]
qed_ll2_rxq_completion+0xba/0x320 [qed]
qed_int_sp_dpc+0x1a7/0x1e0 [qed]
This patch fixes this by accouting skb_shared_info and device
placement padding size bytes when allocating the buffers.
Cc: David S. Miller <davem@davemloft.net>
Fixes: 0a7fb11c23 ("qed: Add Light L2 support")
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e339c6d628 upstream.
If we can't find a free fence register to handle a fault in the GMADR
range just return VM_FAULT_NOPAGE without populating the PTE so that
userspace will retry the access and trigger another fault. Eventually
we should find a free fence and the fault will get properly handled.
A further improvement idea might be to reserve a fence (or one per CPU?)
for the express purpose of handling faults without having to retry. But
that would require some additional work.
Looks like this may have gotten broken originally by
commit 39965b3766 ("drm/i915: don't trash the gtt when running out of fences")
as that changed the errno to -EDEADLK which wasn't handle by the gtt
fault code either. But later in commit 2feeb52859 ("drm/i915/gt: Fix
-EDEADLK handling regression") I changed it again to -ENOBUFS as -EDEADLK
was now getting used for the ww mutex dance. So this fix only makes
sense after that last commit.
Cc: stable@vger.kernel.org
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9479
Fixes: 2feeb52859 ("drm/i915/gt: Fix -EDEADLK handling regression")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231012132801.16292-1-ville.syrjala@linux.intel.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
(cherry picked from commit 7f403caabe811b88ab0de3811ff3f4782c415761)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d920abd1e7 upstream.
From Alon:
"Due to a logical bug in the NVMe-oF/TCP subsystem in the Linux kernel,
a malicious user can cause a UAF and a double free, which may lead to
RCE (may also lead to an LPE in case the attacker already has local
privileges)."
Hence, when a queue initialization fails after the ahash requests are
allocated, it is guaranteed that the queue removal async work will be
called, hence leave the deallocation to the queue removal.
Also, be extra careful not to continue processing the socket, so set
queue rcv_state to NVMET_TCP_RECV_ERR upon a socket error.
Cc: stable@vger.kernel.org
Reported-by: Alon Zahavi <zahavi.alon@gmail.com>
Tested-by: Alon Zahavi <zahavi.alon@gmail.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d351c1ea2d upstream.
mcast packets get looped back to the local machine.
Such packets have a 0-length mac header, we should treat
this like "mac header not set" and abort rule evaluation.
As-is, we just copy data from the network header instead.
Fixes: 96518518cc ("netfilter: add nftables")
Reported-by: Blažej Krajňák <krajnak@levonet.sk>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8e7e27b2ee upstream.
Here is a BUG report about linux-6.1 from syzbot, but it still remains
within upstream:
BUG: KASAN: slab-out-of-bounds in ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
BUG: KASAN: slab-out-of-bounds in ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
Read of size 1 at addr ffff888021acaf3d by task syz-executor128/3632
Call Trace:
kasan_report+0x139/0x170 mm/kasan/report.c:495
ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
vfs_listxattr fs/xattr.c:457 [inline]
listxattr+0x293/0x2d0 fs/xattr.c:804
path_listxattr fs/xattr.c:828 [inline]
__do_sys_llistxattr fs/xattr.c:846 [inline]
Before derefering field members of `ea` in unpacked_ea_size(), we need to
check whether the EA_FULL struct is located in access validate range.
Similarly, when derefering `ea->name` field member, we need to check
whethe the ea->name is located in access validate range, too.
Fixes: be71b5cba2 ("fs/ntfs3: Add attrib operations")
Reported-by: syzbot+9fcea5ef6dc4dc72d334@syzkaller.appspotmail.com
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
[almaz.alexandrovich@paragon-software.com: took the ret variable out of the loop block]
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1f9b94af92 upstream.
Upon investigation of the C reproducer provided by Syzbot, it seemed
the reproducer was trying to mount a corrupted NTFS filesystem, then
issue a rename syscall to some nodes in the filesystem. This can be
shown by modifying the reproducer to only include the mount syscall,
and investigating the filesystem by e.g. `ls` and `rm` commands. As a
result, during the problematic call to `hdr_fine_e`, the `inode` being
supplied did not go through `indx_init`, hence the `cmp` function
pointer was never set.
The fix is simply to check whether `cmp` is not set, and return NULL
if that's the case, in order to be consistent with other error
scenarios of the `hdr_find_e` method. The rationale behind this patch
is that:
- We should prevent crashing the kernel even if the mounted filesystem
is corrupted. Any syscalls made on the filesystem could return
invalid, but the kernel should be able to sustain these calls.
- Only very specific corruption would lead to this bug, so it would be
a pretty rare case in actual usage anyways. Therefore, introducing a
check to specifically protect against this bug seems appropriate.
Because of its rarity, an `unlikely` clause is used to wrap around
this nullity check.
Reported-by: syzbot+60cf892fc31d1f4358fc@syzkaller.appspotmail.com
Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Upstream commit: 63e44bc520
Check the memory operand of INS/OUTS before emulating the instruction.
The #VC exception can get raised from user-space, but the memory operand
can be manipulated to access kernel memory before the emulation actually
begins and after the exception handler has run.
[ bp: Massage commit message. ]
Fixes: 597cfe4821 ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Upstream commit: b9cb9c4558
Check the IO permission bitmap (if present) before emulating IOIO #VC
exceptions for user-space. These permissions are checked by hardware
already before the #VC is raised, but due to the VC-handler decoding
race it needs to be checked again in software.
Fixes: 25189d08e5 ("x86/sev-es: Add support for handling IOIO exceptions")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Dohrmann <erbse.13@gmx.de>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Upstream commit: a37cd2a59d
A virt scenario can be constructed where MMIO memory can be user memory.
When that happens, a race condition opens between when the hardware
raises the #VC and when the #VC handler gets to emulate the instruction.
If the MOVS is replaced with a MOVS accessing kernel memory in that
small race window, then write to kernel memory happens as the access
checks are not done at emulation time.
Disable MMIO emulation in user mode temporarily until a sensible use
case appears and justifies properly handling the race window.
Fixes: 0118b604c2 ("x86/sev-es: Handle MMIO String Instructions")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Dohrmann <erbse.13@gmx.de>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a16eb25b09 upstream.
Per the SDM, "When the local APIC handles a performance-monitoring
counters interrupt, it automatically sets the mask flag in the LVT
performance counter register." Add this behavior to KVM's local APIC
emulation.
Failure to mask the LVTPC entry results in spurious PMIs, e.g. when
running Linux as a guest, PMI handlers that do a "late_ack" spew a large
number of "dazed and confused" spurious NMI warnings.
Fixes: f5132b0138 ("KVM: Expose a version 2 architectural PMU to a guests")
Cc: stable@vger.kernel.org
Signed-off-by: Jim Mattson <jmattson@google.com>
Tested-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230925173448.3518223-3-mizhang@google.com
[sean: massage changelog, correct Fixes]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0288c3e709 upstream.
When the system boots into the crash dump kernel after a panic, the ice
networking device may still have pending transactions that can cause errors
or machine checks when the device is re-enabled. This can prevent the crash
dump kernel from loading the driver or collecting the crash data.
To avoid this issue, perform a function level reset (FLR) on the ice device
via PCIe config space before enabling it on the crash kernel. This will
clear any outstanding transactions and stop all queues and interrupts.
Restore the config space after the FLR, otherwise it was found in testing
that the driver wouldn't load successfully.
The following sequence causes the original issue:
- Load the ice driver with modprobe ice
- Enable SR-IOV with 2 VFs: echo 2 > /sys/class/net/eth0/device/sriov_num_vfs
- Trigger a crash with echo c > /proc/sysrq-trigger
- Load the ice driver again (or let it load automatically) with modprobe ice
- The system crashes again during pcim_enable_device()
Fixes: 837f08fdec ("ice: Add basic driver framework for Intel(R) E800 Series")
Reported-by: Vishal Agrawal <vagrawal@redhat.com>
Reviewed-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Link: https://lore.kernel.org/r/20231011233334.336092-3-jacob.e.keller@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9d1a3c7474 upstream.
bacmp() is a wrapper around memcpy(), which contain compile-time
checks for buffer overflow. Since the hci_conn_request_evt() also calls
bt_dev_dbg() with an implicit NULL pointer check, the compiler is now
aware of a case where 'hdev' is NULL and treats this as meaning that
zero bytes are available:
In file included from net/bluetooth/hci_event.c:32:
In function 'bacmp',
inlined from 'hci_conn_request_evt' at net/bluetooth/hci_event.c:3276:7:
include/net/bluetooth/bluetooth.h:364:16: error: 'memcmp' specified bound 6 exceeds source size 0 [-Werror=stringop-overread]
364 | return memcmp(ba1, ba2, sizeof(bdaddr_t));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Add another NULL pointer check before the bacmp() to ensure the compiler
understands the code flow enough to not warn about it. Since the patch
that introduced the warning is marked for stable backports, this one
should also go that way to avoid introducing build regressions.
Fixes: 1ffc6f8cc3 ("Bluetooth: Reject connection with the device which has same BD_ADDR")
Cc: Kees Cook <keescook@chromium.org>
Cc: "Lee, Chun-Yi" <jlee@suse.com>
Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 35d91d95a0 upstream.
This fixes the following code style problem:
ERROR: that open brace { should be on the previous line
+ if (!bacmp(&hdev->bdaddr, &ev->bdaddr))
+ {
Fixes: 1ffc6f8cc3 ("Bluetooth: Reject connection with the device which has same BD_ADDR")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 92d4abd66f upstream.
When the vhci device is opened in the two-step way, i.e.: open device
then write a vendor packet with requested controller type, the device
shall respond with a vendor packet which includes HCI index of created
interface.
When the virtual HCI is created, the host sends a reset request to the
controller. This request is processed by the vhci_send_frame() function.
However, this request is send by a different thread, so it might happen
that this HCI request will be received before the vendor response is
queued in the read queue. This results in the HCI vendor response and
HCI reset request inversion in the read queue which leads to improper
behavior of btvirt:
> dmesg
[1754256.640122] Bluetooth: MGMT ver 1.22
[1754263.023806] Bluetooth: MGMT ver 1.22
[1754265.043775] Bluetooth: hci1: Opcode 0x c03 failed: -110
In order to synchronize vhci two-step open/setup process with virtual
HCI initialization, this patch adds internal lock when queuing data in
the vhci_send_frame() function.
Signed-off-by: Arkadiusz Bokowy <arkadiusz.bokowy@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c7f59461f5 upstream.
Syzbot reports a warning as follows:
WARNING: CPU: 1 PID: 26946 at net/bluetooth/hci_conn.c:619
hci_conn_timeout+0x122/0x210 net/bluetooth/hci_conn.c:619
...
Call Trace:
<TASK>
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
</TASK>
It is because the HCI_EV_SIMPLE_PAIR_COMPLETE event handler drops
hci_conn directly without check Simple Pairing whether be enabled. But
the Simple Pairing process can only be used if both sides have the
support enabled in the host stack.
Add hci_conn_ssp_enabled() for hci_conn in HCI_EV_IO_CAPA_REQUEST and
HCI_EV_SIMPLE_PAIR_COMPLETE event handlers to fix the problem.
Fixes: 0493684ed2 ("[Bluetooth] Disable disconnect timer during Simple Pairing")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1ffc6f8cc3 upstream.
This change is used to relieve CVE-2020-26555. The description of
the CVE:
Bluetooth legacy BR/EDR PIN code pairing in Bluetooth Core Specification
1.0B through 5.2 may permit an unauthenticated nearby device to spoof
the BD_ADDR of the peer device to complete pairing without knowledge
of the PIN. [1]
The detail of this attack is in IEEE paper:
BlueMirror: Reflections on Bluetooth Pairing and Provisioning Protocols
[2]
It's a reflection attack. The paper mentioned that attacker can induce
the attacked target to generate null link key (zero key) without PIN
code. In BR/EDR, the key generation is actually handled in the controller
which is below HCI.
A condition of this attack is that attacker should change the
BR_ADDR of his hacking device (Host B) to equal to the BR_ADDR with
the target device being attacked (Host A).
Thus, we reject the connection with device which has same BD_ADDR
both on HCI_Create_Connection and HCI_Connection_Request to prevent
the attack. A similar implementation also shows in btstack project.
[3][4]
Cc: stable@vger.kernel.org
Link: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26555 [1]
Link: https://ieeexplore.ieee.org/abstract/document/9474325/authors#authors [2]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3523 [3]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L7297 [4]
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 33155c4aae upstream.
This change is used to relieve CVE-2020-26555. The description of the
CVE:
Bluetooth legacy BR/EDR PIN code pairing in Bluetooth Core Specification
1.0B through 5.2 may permit an unauthenticated nearby device to spoof
the BD_ADDR of the peer device to complete pairing without knowledge
of the PIN. [1]
The detail of this attack is in IEEE paper:
BlueMirror: Reflections on Bluetooth Pairing and Provisioning Protocols
[2]
It's a reflection attack. The paper mentioned that attacker can induce
the attacked target to generate null link key (zero key) without PIN
code. In BR/EDR, the key generation is actually handled in the controller
which is below HCI.
Thus, we can ignore null link key in the handler of "Link Key Notification
event" to relieve the attack. A similar implementation also shows in
btstack project. [3]
v3: Drop the connection when null link key be detected.
v2:
- Used Link: tag instead of Closes:
- Used bt_dev_dbg instead of BT_DBG
- Added Fixes: tag
Cc: stable@vger.kernel.org
Fixes: 55ed8ca10f ("Bluetooth: Implement link key handling for the management interface")
Link: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26555 [1]
Link: https://ieeexplore.ieee.org/abstract/document/9474325/authors#authors [2]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3722 [3]
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7b7820b83f upstream.
Ian Kent reported that for inline symlinks, it's possible for
vfs_readlink to hang on to the target buffer returned by
_vn_get_link_inline long after it's been freed by xfs inode reclaim.
This is a layering violation -- we should never expose XFS internals to
the VFS.
When the symlink has a remote target, we allocate a separate buffer,
copy the internal information, and let the VFS manage the new buffer's
lifetime. Let's adapt the inline code paths to do this too. It's
less efficient, but fixes the layering violation and avoids the need to
adapt the if_data lifetime to rcu rules. Clearly I don't care about
readlink benchmarks.
As a side note, this fixes the minor locking violation where we can
access the inode data fork without taking any locks; proper locking (and
eliminating the possibility of having to switch inode_operations on a
live inode) is essential to online repair coordinating repairs
correctly.
Reported-by: Ian Kent <raven@themaw.net>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Chandan Babu R <chandanbabu@kernel.org>
Acked-by: Leah Rumancik <leah.rumancik@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1faa34672f upstream.
Stephen Rothwell reported htmldocs warning when merging net-next tree:
Documentation/admin-guide/sysctl/net.rst:37: WARNING: Malformed table.
Text in column margin in table line 4.
========= =================== = ========== ==================
Directory Content Directory Content
========= =================== = ========== ==================
802 E802 protocol mptcp Multipath TCP
appletalk Appletalk protocol netfilter Network Filter
ax25 AX25 netrom NET/ROM
bridge Bridging rose X.25 PLP layer
core General parameter tipc TIPC
ethernet Ethernet protocol unix Unix domain sockets
ipv4 IP version 4 x25 X.25 protocol
ipv6 IP version 6
========= =================== = ========== ==================
The warning above is caused by cells in second "Content" column of
/proc/sys/net subdirectory table which are in column margin.
Align these cells against the column header to fix the warning.
Link: https://lore.kernel.org/linux-next/20220823134905.57ed08d5@canb.auug.org.au/
Fixes: 1202cdd665 ("Remove DECnet support from kernel")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20220824035804.204322-1-bagasdotme@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 36ffca1afe upstream.
Defining local versions of NAPI_POLL_WEIGHT with the same
values in the drivers just makes refactoring harder.
This patch covers three more drivers which I missed in
commit 5f012b40ef ("eth: remove copies of the NAPI_POLL_WEIGHT define").
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 223d3a0d30 upstream.
If CONFIG_SWP_EMULATION is not set and
CONFIG_CP15_BARRIER_EMULATION is not set,
aarch64-linux-gnu complained about unused-function :
arch/arm64/kernel/armv8_deprecated.c:67:21: error: ‘aarch32_check_condition’ defined but not used [-Werror=unused-function]
static unsigned int aarch32_check_condition(u32 opcode, u32 psr)
^~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
To fix this warning, modify aarch32_check_condition() with __maybe_unused.
Fixes: 0c5f416219 ("arm64: armv8_deprecated: move aarch32 helper earlier")
Signed-off-by: Ren Zhijie <renzhijie2@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20221124022429.19024-1-renzhijie2@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 124c49b1b5 upstream.
Support for deprecated instructions can be enabled or disabled at
runtime. To handle this, the code in armv8_deprecated.c registers and
unregisters undef_hooks, and makes cross CPU calls to configure HW
support. This is rather complicated, and the synchronization required to
make this safe ends up serializing the handling of instructions which
have been trapped.
This patch simplifies the deprecated instruction handling by removing
the dynamic registration and unregistration, and changing the trap
handling code to determine whether a handler should be invoked. This
removes the need for dynamic list management, and simplifies the locking
requirements, making it possible to handle trapped instructions entirely
in parallel.
Where changing the emulation state requires a cross-call, this is
serialized by locally disabling interrupts, ensuring that the CPU is not
left in an inconsistent state.
To simplify sysctl management, each insn_emulation is given a separate
sysctl table, permitting these to be registered separately. The core
sysctl code will iterate over all of these when walking sysfs.
I've tested this with userspace programs which use each of the
deprecated instructions, and I've concurrently modified the support
level for each of the features back-and-forth between HW and emulated to
check that there are no spurious SIGILLs sent to userspace when the
support level is changed.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20221019144123.612388-10-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f5962add74 upstream.
On CPUs without FEAT_IDST, ID register emulation is slower than it needs
to be, as all threads contend for the same lock to perform the
emulation. This patch reworks the emulation to avoid this unnecessary
contention.
On CPUs with FEAT_IDST (which is mandatory from ARMv8.4 onwards), EL0
accesses to ID registers result in a SYS trap, and emulation of these is
handled with a sys64_hook. These hooks are statically allocated, and no
locking is required to iterate through the hooks and perform the
emulation, allowing emulation to occur in parallel with no contention.
On CPUs without FEAT_IDST, EL0 accesses to ID registers result in an
UNDEFINED exception, and emulation of these accesses is handled with an
undef_hook. When an EL0 MRS instruction is trapped to EL1, the kernel
finds the relevant handler by iterating through all of the undef_hooks,
requiring undef_lock to be held during this lookup.
This locking is only required to safely traverse the list of undef_hooks
(as it can be concurrently modified), and the actual emulation of the
MRS does not require any mutual exclusion. This locking is an
unfortunate bottleneck, especially given that MRS emulation is enabled
unconditionally and is never disabled.
This patch reworks the non-FEAT_IDST MRS emulation logic so that it can
be invoked directly from do_el0_undef(). This removes the bottleneck,
allowing MRS traps to be handled entirely in parallel, and is a stepping
stone to making all of the undef_hooks lock-free.
I've tested this in a 64-vCPU VM on a 64-CPU ThunderX2 host, with a
benchmark which spawns a number of threads which each try to read
ID_AA64ISAR0_EL1 1000000 times. This is vastly more contention than will
ever be seen in realistic usage, but clearly demonstrates the removal of
the bottleneck:
| Threads || Time (seconds) |
| || Before || After |
| || Real | System || Real | System |
|---------++--------+---------++--------+---------|
| 1 || 0.29 | 0.20 || 0.24 | 0.12 |
| 2 || 0.35 | 0.51 || 0.23 | 0.27 |
| 4 || 1.08 | 3.87 || 0.24 | 0.56 |
| 8 || 4.31 | 33.60 || 0.24 | 1.11 |
| 16 || 9.47 | 149.39 || 0.23 | 2.15 |
| 32 || 19.07 | 605.27 || 0.24 | 4.38 |
| 64 || 65.40 | 3609.09 || 0.33 | 11.27 |
Aside from the speedup, there should be no functional change as a result
of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20221019144123.612388-6-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bff8f413c7 upstream.
Currently call_undef_hook() is used to handle UNDEFINED exceptions from
EL0 and EL1. As support for deprecated instructions may be enabled
independently, the handlers for individual instructions are organised as
a linked list of struct undef_hook which can be manipulated dynamically.
As this can be manipulated dynamically, the list is protected with a
raw_spinlock which must be acquired when handling UNDEFINED exceptions
or when manipulating the list of handlers.
This locking is unfortunate as it serialises handling of UNDEFINED
exceptions, and requires RCU to be enabled for lockdep, requiring the
use of RCU_NONIDLE() in resume path of cpu_suspend() since commit:
a2c42bbabb ("arm64: spectre: Prevent lockdep splat on v4 mitigation enable path")
The list of UNDEFINED handlers largely consist of handlers for
exceptions taken from EL0, and the only handler for exceptions taken
from EL1 handles `MSR SSBS, #imm` on CPUs which feature PSTATE.SSBS but
lack the corresponding MSR (Immediate) instruction. Other than this we
never expect to take an UNDEFINED exception from EL1 in normal
operation.
This patch reworks do_el0_undef() to invoke the EL1 SSBS handler
directly, relegating call_undef_hook() to only handle EL0 UNDEFs. This
removes redundant work to iterate the list for EL1 UNDEFs, and removes
the need for locking, permitting EL1 UNDEFs to be handled in parallel
without contention.
The RCU_NONIDLE() call in cpu_suspend() will be removed in a subsequent
patch, as there are other potential issues with the use of
instrumentable code and RCU in the CPU suspend code.
I've tested this by forcing the detection of SSBS on a CPU that doesn't
have it, and verifying that the try_emulate_el1_ssbs() callback is
invoked.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20221019144123.612388-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 61d64a376e upstream.
In general, exceptions taken from EL1 need to be handled separately from
exceptions taken from EL0, as the logic to handle the two cases can be
significantly divergent, and exceptions taken from EL1 typically have
more stringent requirements on locking and instrumentation.
Subsequent patches will rework the way EL1 UNDEFs are handled in order
to address longstanding soundness issues with instrumentation and RCU.
In preparation for that rework, this patch splits the existing
do_undefinstr() handler into separate do_el0_undef() and do_el1_undef()
handlers.
Prior to this patch, do_undefinstr() was marked with NOKPROBE_SYMBOL(),
preventing instrumentation via kprobes. However, do_undefinstr() invokes
other code which can be instrumented, and:
* For UNDEFINED exceptions taken from EL0, there is no risk of recursion
within kprobes. Therefore it is safe for do_el0_undef to be
instrumented with kprobes, and it does not need to be marked with
NOKPROBE_SYMBOL().
* For UNDEFINED exceptions taken from EL1, either:
(a) The exception is has been taken when manipulating SSBS; these cases
are limited and do not occur within code that can be invoked
recursively via kprobes. Hence, in these cases instrumentation
with kprobes is benign.
(b) The exception has been taken for an unknown reason, as other than
manipulating SSBS we do not expect to take UNDEFINED exceptions
from EL1. Any handling of these exception is best-effort.
... and in either case, marking do_el1_undef() with NOKPROBE_SYMBOL()
isn't sufficient to prevent recursion via kprobes as functions it
calls (including die()) are instrumentable via kprobes.
Hence, it's not worthwhile to mark do_el1_undef() with
NOKPROBE_SYMBOL(). The same applies to do_el1_bti() and do_el1_fpac(),
so their NOKPROBE_SYMBOL() annotations are also removed.
Aside from the new instrumentability, there should be no functional
change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20221019144123.612388-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
