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Some Intel processors may use alternate predictors for RETs on
RSB-underflow. This condition may be vulnerable to Branch History
Injection (BHI) and intramode-BTI.
Kernel earlier added spectre_v2 mitigation modes (eIBRS+Retpolines,
eIBRS+LFENCE, Retpolines) which protect indirect CALLs and JMPs against
such attacks. However, on RSB-underflow, RET target prediction may
fallback to alternate predictors. As a result, RET's predicted target
may get influenced by branch history.
A new MSR_IA32_SPEC_CTRL bit (RRSBA_DIS_S) controls this fallback
behavior when in kernel mode. When set, RETs will not take predictions
from alternate predictors, hence mitigating RETs as well. Support for
this is enumerated by CPUID.7.2.EDX[RRSBA_CTRL] (bit2).
For spectre v2 mitigation, when a user selects a mitigation that
protects indirect CALLs and JMPs against BHI and intramode-BTI, set
RRSBA_DIS_S also to protect RETs for RSB-underflow case.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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All the invocations unroll to __x86_return_thunk and this file
must be PIC independent.
This fixes kexec on 64-bit AMD boxes.
[ bp: Fix 32-bit build. ]
Reported-by: Edward Tran <edward.tran@oracle.com>
Reported-by: Awais Tanveer <awais.tanveer@oracle.com>
Suggested-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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NFPROTO_ARP is expecting to find the ARP header at the network offset.
In the particular case of ARP, HTYPE= field shows the initial bytes of
the ethernet header destination MAC address.
netdev out: IN= OUT=bridge0 MACSRC=c2:76:e5:71:e1:de MACDST=36:b0:4a:e2:72:ea MACPROTO=0806 ARP HTYPE=14000 PTYPE=0x4ae2 OPCODE=49782
NFPROTO_NETDEV egress hook is also expecting to find the IP headers at
the network offset.
Fixes: 35b9395104d5 ("netfilter: add generic ARP packet logger")
Reported-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Martin Blumenstingl says:
====================
selftests: forwarding: Install two missing tests
For some distributions (e.g. OpenWrt) we don't want to rely on rsync
to copy the tests to the target as some extra dependencies need to be
installed. The Makefile in tools/testing/selftests/net/forwarding
already installs most of the tests.
This series adds the two missing tests to the list of installed tests.
That way a downstream distribution can build a package using this
Makefile (and add dependencies there as needed).
====================
Link: https://lore.kernel.org/r/20220707135532.1783925-1-martin.blumenstingl@googlemail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When using the Makefile from tools/testing/selftests/net/forwarding/
all tests should be installed. Add no_forwarding.sh to the list of
"to be installed tests" where it has been missing so far.
Fixes: 476a4f05d9b83f ("selftests: forwarding: add a no_forwarding.sh test")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When using the Makefile from tools/testing/selftests/net/forwarding/
all tests should be installed. Add local_termination.sh to the list of
"to be installed tests" where it has been missing so far.
Fixes: 90b9566aa5cd3f ("selftests: forwarding: add a test for local_termination.sh")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull fscache fixes from David Howells:
- Fix a check in fscache_wait_on_volume_collision() in which the
polarity is reversed. It should complain if a volume is still marked
acquisition-pending after 20s, but instead complains if the mark has
been cleared (ie. the condition has cleared).
Also switch an open-coded test of the ACQUIRE_PENDING volume flag to
use the helper function for consistency.
- Not a fix per se, but neaten the code by using a helper to check for
the DROPPED state.
- Fix cachefiles's support for erofs to only flush requests associated
with a released control file, not all requests.
- Fix a race between one process invalidating an object in the cache
and another process trying to look it up.
* tag 'fscache-fixes-20220708' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
fscache: Fix invalidation/lookup race
cachefiles: narrow the scope of flushed requests when releasing fd
fscache: Introduce fscache_cookie_is_dropped()
fscache: Fix if condition in fscache_wait_on_volume_collision()
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Daniel Borkmann says:
====================
bpf 2022-07-08
We've added 3 non-merge commits during the last 2 day(s) which contain
a total of 7 files changed, 40 insertions(+), 24 deletions(-).
The main changes are:
1) Fix cBPF splat triggered by skb not having a mac header, from Eric Dumazet.
2) Fix spurious packet loss in generic XDP when pushing packets out (note
that native XDP is not affected by the issue), from Johan Almbladh.
3) Fix bpf_dynptr_{read,write}() helper signatures with flag argument before
its set in stone as UAPI, from Joanne Koong.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs
bpf: Make sure mac_header was set before using it
xdp: Fix spurious packet loss in generic XDP TX path
====================
Link: https://lore.kernel.org/r/20220708213418.19626-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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CI reported the following splat while running the strace testsuite:
[ 3976.640309] WARNING: CPU: 1 PID: 3570031 at kernel/ptrace.c:272 ptrace_check_attach+0x12e/0x178
[ 3976.640391] CPU: 1 PID: 3570031 Comm: strace Tainted: G OE 5.19.0-20220624.rc3.git0.ee819a77d4e7.300.fc36.s390x #1
[ 3976.640410] Hardware name: IBM 3906 M04 704 (z/VM 7.1.0)
[ 3976.640452] Call Trace:
[ 3976.640454] [<00000000ab4b645a>] ptrace_check_attach+0x132/0x178
[ 3976.640457] ([<00000000ab4b6450>] ptrace_check_attach+0x128/0x178)
[ 3976.640460] [<00000000ab4b6cde>] __s390x_sys_ptrace+0x86/0x160
[ 3976.640463] [<00000000ac03fcec>] __do_syscall+0x1d4/0x200
[ 3976.640468] [<00000000ac04e312>] system_call+0x82/0xb0
[ 3976.640470] Last Breaking-Event-Address:
[ 3976.640471] [<00000000ab4ea3c8>] wait_task_inactive+0x98/0x190
This is because JOBCTL_TRACED is set, but the task is not in TASK_TRACED
state. Caused by ptrace_unfreeze_traced() which does:
task->jobctl &= ~TASK_TRACED
but it should be:
task->jobctl &= ~JOBCTL_TRACED
Fixes: 31cae1eaae4f ("sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Link: https://lkml.kernel.org/r/20220706101625.2100298-1-svens@linux.ibm.com
Link: https://lkml.kernel.org/r/YrHA5UkJLornOdCz@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2101641
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI fixes from Rafael Wysocki:
"These fix two recent regressions related to CPPC support.
Specifics:
- Prevent _CPC from being used if the platform firmware does not
confirm CPPC v2 support via _OSC (Mario Limonciello)
- Allow systems with X86_FEATURE_CPPC set to use _CPC even if CPPC
support cannot be agreed on via _OSC (Mario Limonciello)"
* tag 'acpi-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported
ACPI: CPPC: Only probe for _CPC if CPPC v2 is acked
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix a NULL pointer dereference in a devfreq driver and a runtime
PM framework issue that may cause a supplier device to be suspended
before its consumer.
Specifics:
- Fix NULL pointer dereference related to printing a diagnostic
message in the exynos-bus devfreq driver (Christian Marangi)
- Fix race condition in the runtime PM framework which in some cases
may cause a supplier device to be suspended when its consumer is
still active (Rafael Wysocki)"
* tag 'pm-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM / devfreq: exynos-bus: Fix NULL pointer dereference
PM: runtime: Fix supplier device management during consumer probe
PM: runtime: Redefine pm_runtime_release_supplier()
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git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl
Pull cxl fixes from Vishal Verma:
- Update MAINTAINERS for Ben's email
- Fix cleanup of port devices on failure to probe driver
- Fix endianness in get/set LSA mailbox command structures
- Fix memregion_free() fallback definition
- Fix missing variable payload checks in CXL cmd size validation
* tag 'cxl-fixes-for-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
cxl/mbox: Fix missing variable payload checks in cmd size validation
memregion: Fix memregion_free() fallback definition
cxl/mbox: Use __le32 in get,set_lsa mailbox structures
cxl/core: Use is_endpoint_decoder
cxl: Fix cleanup of port devices on failure to probe driver.
MAINTAINERS: Update Ben's email address
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu fixes from Joerg Roedel:
- fix device setup failures in the Intel VT-d driver when the PASID
table is shared
- fix Intel VT-d device hot-add failure due to wrong device notifier
order
- remove the old IOMMU mailing list from the MAINTAINERS file now that
it has been retired
* tag 'iommu-fixes-v5.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
MAINTAINERS: Remove iommu@lists.linux-foundation.org
iommu/vt-d: Fix RID2PASID setup/teardown failure
iommu/vt-d: Fix PCI bus rescan device hot add
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git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio fixes from Bartosz Golaszewski:
- fix a build error in gpio-vf610
- fix a null-pointer dereference in the GPIO character device code
* tag 'gpio-fixes-for-v5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
gpiolib: cdev: fix null pointer dereference in linereq_free()
gpio: vf610: fix compilation error
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Merge a runtime PM framework cleanup and fix related to device links.
* pm-core:
PM: runtime: Fix supplier device management during consumer probe
PM: runtime: Redefine pm_runtime_release_supplier()
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Pull block fixes from Jens Axboe:
"NVMe pull request with another id quirk addition, and a tracing fix"
* tag 'block-5.19-2022-07-08' of git://git.kernel.dk/linux-block:
nvme: use struct group for generic command dwords
nvme-pci: phison e16 has bogus namespace ids
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Pull io_uring tweak from Jens Axboe:
"Just a minor tweak to an addition made in this release cycle: padding
a 32-bit value that's in a 64-bit union to avoid any potential
funkiness from that"
* tag 'io_uring-5.19-2022-07-08' of git://git.kernel.dk/linux-block:
io_uring: explicit sqe padding for ioctl commands
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev
Pull fbdev fixes from Helge Deller:
- fbcon now prevents switching to screen resolutions which are smaller
than the font size, and prevents enabling a font which is bigger than
the current screen resolution. This fixes vmalloc-out-of-bounds
accesses found by KASAN.
- Guiling Deng fixed a bug where the centered fbdev logo wasn't
displayed correctly if the screen size matched the logo size.
- Hsin-Yi Wang provided a patch to include errno.h to fix build when
CONFIG_OF isn't enabled.
* tag 'for-5.19/fbdev-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
fbcon: Use fbcon_info_from_console() in fbcon_modechange_possible()
fbmem: Check virtual screen sizes in fb_set_var()
fbcon: Prevent that screen size is smaller than font size
fbcon: Disallow setting font bigger than screen size
video: of_display_timing.h: include errno.h
fbdev: fbmem: Fix logo center image dx issue
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We have an optimization in do_zone_finish() to send REQ_OP_ZONE_FINISH only
when necessary, i.e. we don't send REQ_OP_ZONE_FINISH when we assume we
wrote fully into the zone.
The assumption is determined by "alloc_offset == capacity". This condition
won't work if the last ordered extent is canceled due to some errors. In
that case, we consider the zone is deactivated without sending the finish
command while it's still active.
This inconstancy results in activating another block group while we cannot
really activate the underlying zone, which causes the active zone exceeds
errors like below.
BTRFS error (device nvme3n2): allocation failed flags 1, wanted 520192 tree-log 0, relocation: 0
nvme3n2: I/O Cmd(0x7d) @ LBA 160432128, 127 blocks, I/O Error (sct 0x1 / sc 0xbd) MORE DNR
active zones exceeded error, dev nvme3n2, sector 0 op 0xd:(ZONE_APPEND) flags 0x4800 phys_seg 1 prio class 0
nvme3n2: I/O Cmd(0x7d) @ LBA 160432128, 127 blocks, I/O Error (sct 0x1 / sc 0xbd) MORE DNR
active zones exceeded error, dev nvme3n2, sector 0 op 0xd:(ZONE_APPEND) flags 0x4800 phys_seg 1 prio class 0
Fix the issue by removing the optimization for now.
Fixes: 8376d9e1ed8f ("btrfs: zoned: finish superblock zone once no space left for new SB")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The bioc would leak on the normal completion path and also on the RAID56
check (but that one won't happen in practice due to the invalid
combination with zoned mode).
Fixes: 7db1c5d14dcd ("btrfs: zoned: support dev-replace in zoned filesystems")
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[ update changelog ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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extents
When doing a direct IO read or write, we always return -ENOTBLK when we
find a compressed extent (or an inline extent) so that we fallback to
buffered IO. This however is not ideal in case we are in a NOWAIT context
(io_uring for example), because buffered IO can block and we currently
have no support for NOWAIT semantics for buffered IO, so if we need to
fallback to buffered IO we should first signal the caller that we may
need to block by returning -EAGAIN instead.
This behaviour can also result in short reads being returned to user
space, which although it's not incorrect and user space should be able
to deal with partial reads, it's somewhat surprising and even some popular
applications like QEMU (Link tag #1) and MariaDB (Link tag #2) don't
deal with short reads properly (or at all).
The short read case happens when we try to read from a range that has a
non-compressed and non-inline extent followed by a compressed extent.
After having read the first extent, when we find the compressed extent we
return -ENOTBLK from btrfs_dio_iomap_begin(), which results in iomap to
treat the request as a short read, returning 0 (success) and waiting for
previously submitted bios to complete (this happens at
fs/iomap/direct-io.c:__iomap_dio_rw()). After that, and while at
btrfs_file_read_iter(), we call filemap_read() to use buffered IO to
read the remaining data, and pass it the number of bytes we were able to
read with direct IO. Than at filemap_read() if we get a page fault error
when accessing the read buffer, we return a partial read instead of an
-EFAULT error, because the number of bytes previously read is greater
than zero.
So fix this by returning -EAGAIN for NOWAIT direct IO when we find a
compressed or an inline extent.
Reported-by: Dominique MARTINET <dominique.martinet@atmark-techno.com>
Link: https://lore.kernel.org/linux-btrfs/YrrFGO4A1jS0GI0G@atmark-techno.com/
Link: https://jira.mariadb.org/browse/MDEV-27900?focusedCommentId=216582&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-216582
Tested-by: Dominique MARTINET <dominique.martinet@atmark-techno.com>
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This cycle we added support for mounting overlayfs on top of idmapped
mounts. Recently I've started looking into potential corner cases when
trying to add additional tests and I noticed that reporting for POSIX ACLs
is currently wrong when using idmapped layers with overlayfs mounted on top
of it.
I have sent out an patch that fixes this and makes POSIX ACLs work
correctly but the patch is a bit bigger and we're already at -rc5 so I
recommend we simply don't raise SB_POSIXACL when idmapped layers are
used. Then we can fix the VFS part described below for the next merge
window so we can have good exposure in -next.
I'm going to give a rather detailed explanation to both the origin of the
problem and mention the solution so people know what's going on.
Let's assume the user creates the following directory layout and they have
a rootfs /var/lib/lxc/c1/rootfs. The files in this rootfs are owned as you
would expect files on your host system to be owned. For example, ~/.bashrc
for your regular user would be owned by 1000:1000 and /root/.bashrc would
be owned by 0:0. IOW, this is just regular boring filesystem tree on an
ext4 or xfs filesystem.
The user chooses to set POSIX ACLs using the setfacl binary granting the
user with uid 4 read, write, and execute permissions for their .bashrc
file:
setfacl -m u:4:rwx /var/lib/lxc/c2/rootfs/home/ubuntu/.bashrc
Now they to expose the whole rootfs to a container using an idmapped
mount. So they first create:
mkdir -pv /vol/contpool/{ctrover,merge,lowermap,overmap}
mkdir -pv /vol/contpool/ctrover/{over,work}
chown 10000000:10000000 /vol/contpool/ctrover/{over,work}
The user now creates an idmapped mount for the rootfs:
mount-idmapped/mount-idmapped --map-mount=b:0:10000000:65536 \
/var/lib/lxc/c2/rootfs \
/vol/contpool/lowermap
This for example makes it so that
/var/lib/lxc/c2/rootfs/home/ubuntu/.bashrc which is owned by uid and gid
1000 as being owned by uid and gid 10001000 at
/vol/contpool/lowermap/home/ubuntu/.bashrc.
Assume the user wants to expose these idmapped mounts through an overlayfs
mount to a container.
mount -t overlay overlay \
-o lowerdir=/vol/contpool/lowermap, \
upperdir=/vol/contpool/overmap/over, \
workdir=/vol/contpool/overmap/work \
/vol/contpool/merge
The user can do this in two ways:
(1) Mount overlayfs in the initial user namespace and expose it to the
container.
(2) Mount overlayfs on top of the idmapped mounts inside of the container's
user namespace.
Let's assume the user chooses the (1) option and mounts overlayfs on the
host and then changes into a container which uses the idmapping
0:10000000:65536 which is the same used for the two idmapped mounts.
Now the user tries to retrieve the POSIX ACLs using the getfacl command
getfacl -n /vol/contpool/lowermap/home/ubuntu/.bashrc
and to their surprise they see:
# file: vol/contpool/merge/home/ubuntu/.bashrc
# owner: 1000
# group: 1000
user::rw-
user:4294967295:rwx
group::r--
mask::rwx
other::r--
indicating the uid wasn't correctly translated according to the idmapped
mount. The problem is how we currently translate POSIX ACLs. Let's inspect
the callchain in this example:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:0:4k /* initial idmapping */
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get == ovl_posix_acl_xattr_get()
| -> ovl_xattr_get()
| -> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get() /* lower filesystem callback */
|> posix_acl_fix_xattr_to_user()
{
4 = make_kuid(&init_user_ns, 4);
4 = mapped_kuid_fs(&init_user_ns /* no idmapped mount */, 4);
/* FAILURE */
-1 = from_kuid(0:10000000:65536 /* caller's idmapping */, 4);
}
If the user chooses to use option (2) and mounts overlayfs on top of
idmapped mounts inside the container things don't look that much better:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:10000000:65536
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get == ovl_posix_acl_xattr_get()
| -> ovl_xattr_get()
| -> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get() /* lower filesystem callback */
|> posix_acl_fix_xattr_to_user()
{
4 = make_kuid(&init_user_ns, 4);
4 = mapped_kuid_fs(&init_user_ns, 4);
/* FAILURE */
-1 = from_kuid(0:10000000:65536 /* caller's idmapping */, 4);
}
As is easily seen the problem arises because the idmapping of the lower
mount isn't taken into account as all of this happens in do_gexattr(). But
do_getxattr() is always called on an overlayfs mount and inode and thus
cannot possible take the idmapping of the lower layers into account.
This problem is similar for fscaps but there the translation happens as
part of vfs_getxattr() already. Let's walk through an fscaps overlayfs
callchain:
setcap 'cap_net_raw+ep' /var/lib/lxc/c2/rootfs/home/ubuntu/.bashrc
The expected outcome here is that we'll receive the cap_net_raw capability
as we are able to map the uid associated with the fscap to 0 within our
container. IOW, we want to see 0 as the result of the idmapping
translations.
If the user chooses option (1) we get the following callchain for fscaps:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:0:4k /* initial idmapping */
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
-> vfs_getxattr()
-> xattr_getsecurity()
-> security_inode_getsecurity() ________________________________
-> cap_inode_getsecurity() | |
{ V |
10000000 = make_kuid(0:0:4k /* overlayfs idmapping */, 10000000); |
10000000 = mapped_kuid_fs(0:0:4k /* no idmapped mount */, 10000000); |
/* Expected result is 0 and thus that we own the fscap. */ |
0 = from_kuid(0:10000000:65536 /* caller's idmapping */, 10000000); |
} |
-> vfs_getxattr_alloc() |
-> handler->get == ovl_other_xattr_get() |
-> vfs_getxattr() |
-> xattr_getsecurity() |
-> security_inode_getsecurity() |
-> cap_inode_getsecurity() |
{ |
0 = make_kuid(0:0:4k /* lower s_user_ns */, 0); |
10000000 = mapped_kuid_fs(0:10000000:65536 /* idmapped mount */, 0); |
10000000 = from_kuid(0:0:4k /* overlayfs idmapping */, 10000000); |
|____________________________________________________________________|
}
-> vfs_getxattr_alloc()
-> handler->get == /* lower filesystem callback */
And if the user chooses option (2) we get:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:10000000:65536
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
-> vfs_getxattr()
-> xattr_getsecurity()
-> security_inode_getsecurity() _______________________________
-> cap_inode_getsecurity() | |
{ V |
10000000 = make_kuid(0:10000000:65536 /* overlayfs idmapping */, 0); |
10000000 = mapped_kuid_fs(0:0:4k /* no idmapped mount */, 10000000); |
/* Expected result is 0 and thus that we own the fscap. */ |
0 = from_kuid(0:10000000:65536 /* caller's idmapping */, 10000000); |
} |
-> vfs_getxattr_alloc() |
-> handler->get == ovl_other_xattr_get() |
|-> vfs_getxattr() |
-> xattr_getsecurity() |
-> security_inode_getsecurity() |
-> cap_inode_getsecurity() |
{ |
0 = make_kuid(0:0:4k /* lower s_user_ns */, 0); |
10000000 = mapped_kuid_fs(0:10000000:65536 /* idmapped mount */, 0); |
0 = from_kuid(0:10000000:65536 /* overlayfs idmapping */, 10000000); |
|____________________________________________________________________|
}
-> vfs_getxattr_alloc()
-> handler->get == /* lower filesystem callback */
We can see how the translation happens correctly in those cases as the
conversion happens within the vfs_getxattr() helper.
For POSIX ACLs we need to do something similar. However, in contrast to
fscaps we cannot apply the fix directly to the kernel internal posix acl
data structure as this would alter the cached values and would also require
a rework of how we currently deal with POSIX ACLs in general which almost
never take the filesystem idmapping into account (the noteable exception
being FUSE but even there the implementation is special) and instead
retrieve the raw values based on the initial idmapping.
The correct values are then generated right before returning to
userspace. The fix for this is to move taking the mount's idmapping into
account directly in vfs_getxattr() instead of having it be part of
posix_acl_fix_xattr_to_user().
To this end we simply move the idmapped mount translation into a separate
step performed in vfs_{g,s}etxattr() instead of in
posix_acl_fix_xattr_{from,to}_user().
To see how this fixes things let's go back to the original example. Assume
the user chose option (1) and mounted overlayfs on top of idmapped mounts
on the host:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:0:4k /* initial idmapping */
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| |> __vfs_getxattr()
| | -> handler->get == ovl_posix_acl_xattr_get()
| | -> ovl_xattr_get()
| | -> vfs_getxattr()
| | |> __vfs_getxattr()
| | | -> handler->get() /* lower filesystem callback */
| | |> posix_acl_getxattr_idmapped_mnt()
| | {
| | 4 = make_kuid(&init_user_ns, 4);
| | 10000004 = mapped_kuid_fs(0:10000000:65536 /* lower idmapped mount */, 4);
| | 10000004 = from_kuid(&init_user_ns, 10000004);
| | |_______________________
| | } |
| | |
| |> posix_acl_getxattr_idmapped_mnt() |
| { |
| V
| 10000004 = make_kuid(&init_user_ns, 10000004);
| 10000004 = mapped_kuid_fs(&init_user_ns /* no idmapped mount */, 10000004);
| 10000004 = from_kuid(&init_user_ns, 10000004);
| } |_________________________________________________
| |
| |
|> posix_acl_fix_xattr_to_user() |
{ V
10000004 = make_kuid(0:0:4k /* init_user_ns */, 10000004);
/* SUCCESS */
4 = from_kuid(0:10000000:65536 /* caller's idmapping */, 10000004);
}
And similarly if the user chooses option (1) and mounted overayfs on top of
idmapped mounts inside the container:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:10000000:65536
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| |> __vfs_getxattr()
| | -> handler->get == ovl_posix_acl_xattr_get()
| | -> ovl_xattr_get()
| | -> vfs_getxattr()
| | |> __vfs_getxattr()
| | | -> handler->get() /* lower filesystem callback */
| | |> posix_acl_getxattr_idmapped_mnt()
| | {
| | 4 = make_kuid(&init_user_ns, 4);
| | 10000004 = mapped_kuid_fs(0:10000000:65536 /* lower idmapped mount */, 4);
| | 10000004 = from_kuid(&init_user_ns, 10000004);
| | |_______________________
| | } |
| | |
| |> posix_acl_getxattr_idmapped_mnt() |
| { V
| 10000004 = make_kuid(&init_user_ns, 10000004);
| 10000004 = mapped_kuid_fs(&init_user_ns /* no idmapped mount */, 10000004);
| 10000004 = from_kuid(0(&init_user_ns, 10000004);
| |_________________________________________________
| } |
| |
|> posix_acl_fix_xattr_to_user() |
{ V
10000004 = make_kuid(0:0:4k /* init_user_ns */, 10000004);
/* SUCCESS */
4 = from_kuid(0:10000000:65536 /* caller's idmappings */, 10000004);
}
The last remaining problem we need to fix here is ovl_get_acl(). During
ovl_permission() overlayfs will call:
ovl_permission()
-> generic_permission()
-> acl_permission_check()
-> check_acl()
-> get_acl()
-> inode->i_op->get_acl() == ovl_get_acl()
> get_acl() /* on the underlying filesystem)
->inode->i_op->get_acl() == /*lower filesystem callback */
-> posix_acl_permission()
passing through the get_acl request to the underlying filesystem. This will
retrieve the acls stored in the lower filesystem without taking the
idmapping of the underlying mount into account as this would mean altering
the cached values for the lower filesystem. The simple solution is to have
ovl_get_acl() simply duplicate the ACLs, update the values according to the
idmapped mount and return it to acl_permission_check() so it can be used in
posix_acl_permission(). Since overlayfs doesn't cache ACLs they'll be
released right after.
Link: https://github.com/brauner/mount-idmapped/issues/9
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: linux-unionfs@vger.kernel.org
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Fixes: bc70682a497c ("ovl: support idmapped layers")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
|
|
This reverts commit c9cad937c0c58618fe5b0310fd539a854dc1ae95.
This is part of a revert of the following commits:
commit 708d19d9f362 ("drm/amdgpu: move internal vram_mgr function into the C file")
commit 5e3f1e7729ec ("drm/amdgpu: fix start calculation in amdgpu_vram_mgr_new")
commit c9cad937c0c5 ("drm/amdgpu: add drm buddy support to amdgpu")
[WHY]
Few users reported garbaged graphics as soon as x starts,
reverting until this can be resolved.
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220708093047.492662-3-Arunpravin.PaneerSelvam@amd.com
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
|
|
Kuniyuki Iwashima says:
====================
sysctl: Fix data-races around ipv4_table.
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
The first half of this series changes some proc handlers used in ipv4_table
to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the
sysctl side. Then, the second half adds READ_ONCE() to the other readers
of ipv4_table.
Changes:
v2:
* Drop some changes that makes backporting difficult
* First cleanup patch
* Lockless helpers and .proc_handler changes
* Drop the tracing part for .sysctl_mem
* Steve already posted a fix
* Drop int-to-bool change for cipso
* Should be posted to net-next later
* Drop proc_dobool() change
* Can be included in another series
v1: https://lore.kernel.org/netdev/20220706052130.16368-1-kuniyu@amazon.com/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
While reading sysctl_fib_sync_mem, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid a data-race.
Fixes: 9ab948a91b2c ("ipv4: Allow amount of dirty memory from fib resizing to be controllable")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
While reading icmp sysctl variables, they can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.
Fixes: 4cdf507d5452 ("icmp: add a global rate limitation")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
While reading cipso sysctl variables, they can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.
Fixes: 446fda4f2682 ("[NetLabel]: CIPSOv4 engine")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
While reading .sysctl_mem, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
While reading inetpeer sysctl variables, they can be changed
concurrently. So, we need to add READ_ONCE() to avoid data-races.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
While reading sysctl_tcp_max_orphans, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid a data-race.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
This patch changes proc_dointvec_jiffies() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side. For now,
proc_dointvec_jiffies() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
This patch changes proc_doulongvec_minmax() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side. For now,
proc_doulongvec_minmax() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
This patch changes proc_douintvec_minmax() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side. For now,
proc_douintvec_minmax() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.
Fixes: 61d9b56a8920 ("sysctl: add unsigned int range support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
This patch changes proc_dointvec_minmax() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side. For now,
proc_dointvec_minmax() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
This patch changes proc_douintvec() to use READ_ONCE() and WRITE_ONCE()
internally to fix data-races on the sysctl side. For now, proc_douintvec()
itself is tolerant to a data-race, but we still need to add annotations on
the other subsystem's side.
Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
A sysctl variable is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
This patch changes proc_dointvec() to use READ_ONCE() and WRITE_ONCE()
internally to fix data-races on the sysctl side. For now, proc_dointvec()
itself is tolerant to a data-race, but we still need to add annotations on
the other subsystem's side.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The trace event sock_exceed_buf_limit saves the prot->sysctl_mem pointer
and then dereferences it in the TP_printk() portion. This is unsafe as the
TP_printk() portion is executed at the time the buffer is read. That is,
it can be seconds, minutes, days, months, even years later. If the proto
is freed, then this dereference will can also lead to a kernel crash.
Instead, save the sysctl_mem array into the ring buffer and have the
TP_printk() reference that instead. This is the proper and safe way to
read pointers in trace events.
Link: https://lore.kernel.org/all/20220706052130.16368-12-kuniyu@amazon.com/
Cc: stable@vger.kernel.org
Fixes: 3847ce32aea9f ("core: add tracepoints for queueing skb to rcvbuf")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
There are some VM configurations which have Skylake model but do not
support IBPB. In those cases, when using retbleed=ibpb, userspace is going
to be killed and kernel is going to panic.
If the CPU does not support IBPB, warn and proceed with the auto option. Also,
do not fallback to IBPB on AMD/Hygon systems if it is not supported.
Fixes: 3ebc17006888 ("x86/bugs: Add retbleed=ibpb")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
|
|
Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
added the bpf_dynptr_write() and bpf_dynptr_read() APIs.
However, it will be needed for some dynptr types to pass in flags as
well (e.g. when writing to a skb, the user may like to invalidate the
hash or recompute the checksum).
This patch adds a "u64 flags" arg to the bpf_dynptr_read() and
bpf_dynptr_write() APIs before their UAPI signature freezes where
we then cannot change them anymore with a 5.19.x released kernel.
Fixes: 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20220706232547.4016651-1-joannelkoong@gmail.com
|
|
The IOMMU mailing list has moved to iommu@lists.linux.dev
and the old list should bounce by now. Remove it from the
MAINTAINERS file.
Cc: stable@vger.kernel.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220706103331.10215-1-joro@8bytes.org
|
|
Accidentally noticed, that this driver is the only user of
while (time_after(jiffies...)).
It looks like typo, because likely this while loop will finish after 1st
iteration, because time_after() returns true when 1st argument _is after_
2nd one.
There is one possible problem with this poll loop: the scheduler could put
the thread to sleep, and it does not get woken up for
OCELOT_FDMA_CH_SAFE_TIMEOUT_US. During that time, the hardware has done
its thing, but you exit the while loop and return -ETIMEDOUT.
Fix it by using sane poll API that avoids all problems described above
Fixes: 753a026cfec1 ("net: ocelot: add FDMA support")
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220706132845.27968-1-paskripkin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux
Saeed Mahameed says:
====================
mlx5 fixes 2022-07-06
This series provides bug fixes to mlx5 driver.
* tag 'mlx5-fixes-2022-07-06' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux:
net/mlx5e: Ring the TX doorbell on DMA errors
net/mlx5e: Fix capability check for updating vnic env counters
net/mlx5e: CT: Use own workqueue instead of mlx5e priv
net/mlx5: Lag, correct get the port select mode str
net/mlx5e: Fix enabling sriov while tc nic rules are offloaded
net/mlx5e: kTLS, Fix build time constant test in RX
net/mlx5e: kTLS, Fix build time constant test in TX
net/mlx5: Lag, decouple FDB selection and shared FDB
net/mlx5: TC, allow offload from uplink to other PF's VF
====================
Link: https://lore.kernel.org/r/20220706231309.38579-1-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Renaming interfaces using udevd depends on the interface being registered
before its netdev is registered. Otherwise, udevd reads an empty
phys_port_name value, resulting in the interface not being renamed.
Fix this by registering the interface before registering its netdev
by invoking am65_cpsw_nuss_register_devlink() before invoking
register_netdev() for the interface.
Move the function call to devlink_port_type_eth_set(), invoking it after
register_netdev() is invoked, to ensure that netlink notification for the
port state change is generated after the netdev is completely initialized.
Fixes: 58356eb31d60 ("net: ti: am65-cpsw-nuss: Add devlink support")
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Link: https://lore.kernel.org/r/20220706070208.12207-1-s-vadapalli@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
There is a long-standing issue with the Synopsys DWC Ethernet driver
for Tegra194 where random system crashes have been observed [0]. The
problem occurs when the split header feature is enabled in the stmmac
driver. In the bad case, a larger than expected buffer length is
received and causes the calculation of the total buffer length to
overflow. This results in a very large buffer length that causes the
kernel to crash. Why this larger buffer length is received is not clear,
however, the feedback from the NVIDIA design team is that the split
header feature is not supported for Tegra194. Therefore, disable split
header support for Tegra194 to prevent these random crashes from
occurring.
[0] https://lore.kernel.org/linux-tegra/b0b17697-f23e-8fa5-3757-604a86f3a095@nvidia.com/
Fixes: 67afd6d1cfdf ("net: stmmac: Add Split Header support and enable it in XGMAC cores")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20220706083913.13750-1-jonathanh@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Pull NVMe fixes from Christoph:
"nvme fixes for Linux 5.19
- another bogus identifier quirk (Keith Busch)
- use struct group in the tracer to avoid a gcc warning (Keith Busch)"
* tag 'nvme-5.19-2022-07-07' of git://git.infradead.org/nvme:
nvme: use struct group for generic command dwords
nvme-pci: phison e16 has bogus namespace ids
|
|
32 bit sqe->cmd_op is an union with 64 bit values. It's always a good
idea to do padding explicitly. Also zero check it in prep, so it can be
used in the future if needed without compatibility concerns.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e6b95a05e970af79000435166185e85b196b2ba2.1657202417.git.asml.silence@gmail.com
[axboe: turn bitwise OR into logical variant]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
This patch ensures that the clock notifier is unregistered
when driver probe is returning error.
Fixes: df8eb5691c48 ("i2c: Add driver for Cadence I2C controller")
Signed-off-by: Satish Nagireddy <satish.nagireddy@getcruise.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux
Pull a devfreq fix for 5.19-rc6 from Chanwoo Choi:
"- Fix exynos-bus NULL pointer dereference by correctly using the local
generated freq_table to output the debug values instead of using the
profile freq_table that is not used in the driver."
* tag 'devfreq-fixes-for-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux:
PM / devfreq: exynos-bus: Fix NULL pointer dereference
|
|
Fix exynos-bus NULL pointer dereference by correctly using the local
generated freq_table to output the debug values instead of using the
profile freq_table that is not used in the driver.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: b5d281f6c16d ("PM / devfreq: Rework freq_table to be local to devfreq struct")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
|
|
Kajetan Puchalski reports crash on ARM, with backtrace of:
__nf_ct_delete_from_lists
nf_ct_delete
early_drop
__nf_conntrack_alloc
Unlike atomic_inc_not_zero, refcount_inc_not_zero is not a full barrier.
conntrack uses SLAB_TYPESAFE_BY_RCU, i.e. it is possible that a 'newly'
allocated object is still in use on another CPU:
CPU1 CPU2
encounter 'ct' during hlist walk
delete_from_lists
refcount drops to 0
kmem_cache_free(ct);
__nf_conntrack_alloc() // returns same object
refcount_inc_not_zero(ct); /* might fail */
/* If set, ct is public/in the hash table */
test_bit(IPS_CONFIRMED_BIT, &ct->status);
In case CPU1 already set refcount back to 1, refcount_inc_not_zero()
will succeed.
The expected possibilities for a CPU that obtained the object 'ct'
(but no reference so far) are:
1. refcount_inc_not_zero() fails. CPU2 ignores the object and moves to
the next entry in the list. This happens for objects that are about
to be free'd, that have been free'd, or that have been reallocated
by __nf_conntrack_alloc(), but where the refcount has not been
increased back to 1 yet.
2. refcount_inc_not_zero() succeeds. CPU2 checks the CONFIRMED bit
in ct->status. If set, the object is public/in the table.
If not, the object must be skipped; CPU2 calls nf_ct_put() to
un-do the refcount increment and moves to the next object.
Parallel deletion from the hlists is prevented by a
'test_and_set_bit(IPS_DYING_BIT, &ct->status);' check, i.e. only one
cpu will do the unlink, the other one will only drop its reference count.
Because refcount_inc_not_zero is not a full barrier, CPU2 may try to
delete an object that is not on any list:
1. refcount_inc_not_zero() successful (refcount inited to 1 on other CPU)
2. CONFIRMED test also successful (load was reordered or zeroing
of ct->status not yet visible)
3. delete_from_lists unlinks entry not on the hlist, because
IPS_DYING_BIT is 0 (already cleared).
2) is already wrong: CPU2 will handle a partially initited object
that is supposed to be private to CPU1.
Add needed barriers when refcount_inc_not_zero() is successful.
It also inserts a smp_wmb() before the refcount is set to 1 during
allocation.
Because other CPU might still see the object, refcount_set(1)
"resurrects" it, so we need to make sure that other CPUs will also observe
the right content. In particular, the CONFIRMED bit test must only pass
once the object is fully initialised and either in the hash or about to be
inserted (with locks held to delay possible unlink from early_drop or
gc worker).
I did not change flow_offload_alloc(), as far as I can see it should call
refcount_inc(), not refcount_inc_not_zero(): the ct object is attached to
the skb so its refcount should be >= 1 in all cases.
v2: prefer smp_acquire__after_ctrl_dep to smp_rmb (Will Deacon).
v3: keep smp_acquire__after_ctrl_dep close to refcount_inc_not_zero call
add comment in nf_conntrack_netlink, no control dependency there
due to locks.
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/all/Yr7WTfd6AVTQkLjI@e126311.manchester.arm.com/
Reported-by: Kajetan Puchalski <kajetan.puchalski@arm.com>
Diagnosed-by: Will Deacon <will@kernel.org>
Fixes: 719774377622 ("netfilter: conntrack: convert to refcount_t api")
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Will Deacon <will@kernel.org>
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