25 Jun, 2020
2 commits
-
Avoids issuing C-file warnings for vmlinux.
Signed-off-by: Peter Zijlstra (Intel)
Link: https://lkml.kernel.org/r/20200618144801.701257527@infradead.org -
The first working GCC version to satisfy
CC_HAS_WORKING_NOSANITIZE_ADDRESS is GCC 8.3.0.Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89124
Reported-by: Stephen Rothwell
Signed-off-by: Marco Elver
Signed-off-by: Peter Zijlstra (Intel)
Link: https://lkml.kernel.org/r/20200623112448.GA208112@elver.google.com
16 Jun, 2020
1 commit
-
UBSAN is supported since GCC 4.9, which unfortunately did not yet have
__has_attribute(). To work around, the __GCC4_has_attribute workaround
requires defining which compiler version supports the given attribute.In the case of no_sanitize_undefined, it is the first version that
supports UBSAN, which is GCC 4.9.Reported-by: kernel test robot
Signed-off-by: Marco Elver
Signed-off-by: Peter Zijlstra (Intel)
Reviewed-by: Miguel Ojeda
Link: https://lkml.kernel.org/r/20200615231529.GA119644@google.com
15 Jun, 2020
12 commits
-
Explain the rationale for annotating WARN(), even though, strictly
speaking printk() and friends are very much not safe in many of the
places we put them.Signed-off-by: Peter Zijlstra (Intel)
-
The UBSAN instrumentation only inserts external CALLs when things go
'BAD', much like WARN(). So treat them similar to WARN()s for noinstr,
that is: allow them, at the risk of taking the machine down, to get
their message out.Suggested-by: Marco Elver
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Marco Elver -
vmlinux.o: warning: objtool: exc_nmi()+0x12: call to cpumask_test_cpu.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: mce_check_crashing_cpu()+0x12: call to cpumask_test_cpu.constprop.0()leaves .noinstr.text sectioncpumask_test_cpu()
test_bit()
instrument_atomic_read()
arch_test_bit()Signed-off-by: Peter Zijlstra (Intel)
-
Adds the portable definitions for __no_sanitize_address, and
__no_sanitize_undefined, and subsequently changes noinstr to use the
attributes to disable instrumentation via KASAN or UBSAN.Reported-by: syzbot+dc1fa714cb070b184db5@syzkaller.appspotmail.com
Signed-off-by: Marco Elver
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Miguel Ojeda
Link: https://lore.kernel.org/lkml/000000000000d2474c05a6c938fe@google.com/ -
Adds config variable CC_HAS_WORKING_NOSANITIZE_ADDRESS, which will be
true if we have a compiler that does not fail builds due to
no_sanitize_address functions. This does not yet mean they work as
intended, but for automated build-tests, this is the minimum
requirement.For example, we require that __always_inline functions used from
no_sanitize_address functions do not generate instrumentation. On GCC
Signed-off-by: Marco Elver
Signed-off-by: Peter Zijlstra (Intel)
Reviewed-by: Nick Desaulniers
Acked-by: Andrey Konovalov
Link: https://lkml.kernel.org/r/20200602175859.GC2604@hirez.programming.kicks-ass.net -
The 'noinstr' function attribute means no-instrumentation, this should
very much include *SAN. Because lots of that is broken at present,
only include KCSAN for now, as that is limited to clang11, which has
sane function attribute behaviour.Signed-off-by: Peter Zijlstra (Intel)
-
There are no more user of this function attribute, also, with us now
actively supporting '__no_kcsan inline' it doesn't make sense to have
in any case.Signed-off-by: Peter Zijlstra (Intel)
-
Now that KCSAN relies on -tsan-distinguish-volatile we no longer need
the annotation for constant_test_bit(). Remove it.Signed-off-by: Peter Zijlstra (Intel)
-
Pull SafeSetID update from Micah Morton:
"Add additional LSM hooks for SafeSetIDSafeSetID is capable of making allow/deny decisions for set*uid calls
on a system, and we want to add similar functionality for set*gid
calls.The work to do that is not yet complete, so probably won't make it in
for v5.8, but we are looking to get this simple patch in for v5.8
since we have it ready.We are planning on the rest of the work for extending the SafeSetID
LSM being merged during the v5.9 merge window"* tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux:
security: Add LSM hooks to set*gid syscalls -
The SafeSetID LSM uses the security_task_fix_setuid hook to filter
set*uid() syscalls according to its configured security policy. In
preparation for adding analagous support in the LSM for set*gid()
syscalls, we add the requisite hook here. Tested by putting print
statements in the security_task_fix_setgid hook and seeing them get hit
during kernel boot.Signed-off-by: Thomas Cedeno
Signed-off-by: Micah Morton -
Pull btrfs updates from David Sterba:
"This reverts the direct io port to iomap infrastructure of btrfs
merged in the first pull request. We found problems in invalidate page
that don't seem to be fixable as regressions or without changing iomap
code that would not affect other filesystems.There are four reverts in total, but three of them are followup
cleanups needed to revert a43a67a2d715 cleanly. The result is the
buffer head based implementation of direct io.Reverts are not great, but under current circumstances I don't see
better options"* tag 'for-5.8-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: switch to iomap_dio_rw() for dio"
Revert "fs: remove dio_end_io()"
Revert "btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK"
Revert "btrfs: split btrfs_direct_IO to read and write part"
14 Jun, 2020
25 commits
-
Pull networking fixes from David Miller:
1) Fix cfg80211 deadlock, from Johannes Berg.
2) RXRPC fails to send norigications, from David Howells.
3) MPTCP RM_ADDR parsing has an off by one pointer error, fix from
Geliang Tang.4) Fix crash when using MSG_PEEK with sockmap, from Anny Hu.
5) The ucc_geth driver needs __netdev_watchdog_up exported, from
Valentin Longchamp.6) Fix hashtable memory leak in dccp, from Wang Hai.
7) Fix how nexthops are marked as FDB nexthops, from David Ahern.
8) Fix mptcp races between shutdown and recvmsg, from Paolo Abeni.
9) Fix crashes in tipc_disc_rcv(), from Tuong Lien.
10) Fix link speed reporting in iavf driver, from Brett Creeley.
11) When a channel is used for XSK and then reused again later for XSK,
we forget to clear out the relevant data structures in mlx5 which
causes all kinds of problems. Fix from Maxim Mikityanskiy.12) Fix memory leak in genetlink, from Cong Wang.
13) Disallow sockmap attachments to UDP sockets, it simply won't work.
From Lorenz Bauer.* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (83 commits)
net: ethernet: ti: ale: fix allmulti for nu type ale
net: ethernet: ti: am65-cpsw-nuss: fix ale parameters init
net: atm: Remove the error message according to the atomic context
bpf: Undo internal BPF_PROBE_MEM in BPF insns dump
libbpf: Support pre-initializing .bss global variables
tools/bpftool: Fix skeleton codegen
bpf: Fix memlock accounting for sock_hash
bpf: sockmap: Don't attach programs to UDP sockets
bpf: tcp: Recv() should return 0 when the peer socket is closed
ibmvnic: Flush existing work items before device removal
genetlink: clean up family attributes allocations
net: ipa: header pad field only valid for AP->modem endpoint
net: ipa: program upper nibbles of sequencer type
net: ipa: fix modem LAN RX endpoint id
net: ipa: program metadata mask differently
ionic: add pcie_print_link_status
rxrpc: Fix race between incoming ACK parser and retransmitter
net/mlx5: E-Switch, Fix some error pointer dereferences
net/mlx5: Don't fail driver on failure to create debugfs
net/mlx5e: CT: Fix ipv6 nat header rewrite actions
... -
This reverts commit a43a67a2d715540c1368b9501a22b0373b5874c0.
This patch reverts the main part of switching direct io implementation
to iomap infrastructure. There's a problem in invalidate page that
couldn't be solved as regression in this development cycle.The problem occurs when buffered and direct io are mixed, and the ranges
overlap. Although this is not recommended, filesystems implement
measures or fallbacks to make it somehow work. In this case, fallback to
buffered IO would be an option for btrfs (this already happens when
direct io is done on compressed data), but the change would be needed in
the iomap code, bringing new semantics to other filesystems.Another problem arises when again the buffered and direct ios are mixed,
invalidation fails, then -EIO is set on the mapping and fsync will fail,
though there's no real error.There have been discussions how to fix that, but revert seems to be the
least intrusive option.Link: https://lore.kernel.org/linux-btrfs/20200528192103.xm45qoxqmkw7i5yl@fiona/
Signed-off-by: David Sterba -
On AM65xx MCU CPSW2G NUSS and 66AK2E/L NUSS allmulti setting does not allow
unregistered mcast packets to pass.This happens, because ALE VLAN entries on these SoCs do not contain port
masks for reg/unreg mcast packets, but instead store indexes of
ALE_VLAN_MASK_MUXx_REG registers which intended for store port masks for
reg/unreg mcast packets.
This path was missed by commit 9d1f6447274f ("net: ethernet: ti: ale: fix
seeing unreg mcast packets with promisc and allmulti disabled").Hence, fix it by taking into account ALE type in cpsw_ale_set_allmulti().
Fixes: 9d1f6447274f ("net: ethernet: ti: ale: fix seeing unreg mcast packets with promisc and allmulti disabled")
Signed-off-by: Grygorii Strashko
Signed-off-by: David S. Miller -
The ALE parameters structure is created on stack, so it has to be reset
before passing to cpsw_ale_create() to avoid garbage values.Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
Signed-off-by: Grygorii Strashko
Signed-off-by: David S. Miller -
Alexei Starovoitov says:
====================
pull-request: bpf 2020-06-12The following pull-request contains BPF updates for your *net* tree.
We've added 26 non-merge commits during the last 10 day(s) which contain
a total of 27 files changed, 348 insertions(+), 93 deletions(-).The main changes are:
1) sock_hash accounting fix, from Andrey.
2) libbpf fix and probe_mem sanitizing, from Andrii.
3) sock_hash fixes, from Jakub.
4) devmap_val fix, from Jesper.
5) load_bytes_relative fix, from YiFei.
====================Signed-off-by: David S. Miller
-
Looking into the context (atomic!) and the error message should be dropped.
Signed-off-by: Liao Pingfang
Signed-off-by: David S. Miller -
Pull more cifs updates from Steve French:
"12 cifs/smb3 fixes, 2 for stable.- add support for idsfromsid on create and chgrp/chown allowing
ability to save owner information more naturally for some workloads- improve query info (getattr) when SMB3.1.1 posix extensions are
negotiated by using new query info level"* tag '5.8-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
smb3: Add debug message for new file creation with idsfromsid mount option
cifs: fix chown and chgrp when idsfromsid mount option enabled
smb3: allow uid and gid owners to be set on create with idsfromsid mount option
smb311: Add tracepoints for new compound posix query info
smb311: add support for using info level for posix extensions query
smb311: Add support for lookup with posix extensions query info
smb311: Add support for SMB311 query info (non-compounded)
SMB311: Add support for query info using posix extensions (level 100)
smb3: add indatalen that can be a non-zero value to calculation of credit charge in smb2 ioctl
smb3: fix typo in mount options displayed in /proc/mounts
cifs: Add get_security_type_str function to return sec type.
smb3: extend fscache mount volume coherency check -
Let's keep "git status" happy and quiet.
Fixes: 9762dc1432e1 ("samples: add binderfs sample program
Fixes: fca5e94921d5 ("samples: binderfs: really compile this sample and fix build issues")
Signed-off-by: Linus Torvalds -
I'm not convinced the script makes useful automaed help lines anyway,
but since we're trying to deprecate the use of "---help---" in Kconfig
files, let's fix the doc example code too.See commit a7f7f6248d97 ("treewide: replace '---help---' in Kconfig
files with 'help'")Cc: Masahiro Yamada
Signed-off-by: Linus Torvalds -
Pull more Kbuild updates from Masahiro Yamada:
- fix build rules in binderfs sample
- fix build errors when Kbuild recurses to the top Makefile
- covert '---help---' in Kconfig to 'help'
* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
treewide: replace '---help---' in Kconfig files with 'help'
kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
samples: binderfs: really compile this sample and fix build issues -
Pull more SCSI updates from James Bottomley:
"This is the set of changes collected since just before the merge
window opened. It's mostly minor fixes in drivers.The one non-driver set is the three optical disk (sr) changes where
two are error path fixes and one is a helper conversion.The big driver change is the hpsa compat_alloc_userspace rework by Al
so he can kill the remaining user. This has been tested and acked by
the maintainer"* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (21 commits)
scsi: acornscsi: Fix an error handling path in acornscsi_probe()
scsi: storvsc: Remove memset before memory freeing in storvsc_suspend()
scsi: cxlflash: Remove an unnecessary NULL check
scsi: ibmvscsi: Don't send host info in adapter info MAD after LPM
scsi: sr: Fix sr_probe() missing deallocate of device minor
scsi: sr: Fix sr_probe() missing mutex_destroy
scsi: st: Convert convert get_user_pages() --> pin_user_pages()
scsi: target: Rename target_setup_cmd_from_cdb() to target_cmd_parse_cdb()
scsi: target: Fix NULL pointer dereference
scsi: target: Initialize LUN in transport_init_se_cmd()
scsi: target: Factor out a new helper, target_cmd_init_cdb()
scsi: hpsa: hpsa_ioctl(): Tidy up a bit
scsi: hpsa: Get rid of compat_alloc_user_space()
scsi: hpsa: Don't bother with vmalloc for BIG_IOCTL_Command_struct
scsi: hpsa: Lift {BIG_,}IOCTL_Command_struct copy{in,out} into hpsa_ioctl()
scsi: ufs: Remove redundant urgent_bkop_lvl initialization
scsi: ufs: Don't update urgent bkops level when toggling auto bkops
scsi: qedf: Remove redundant initialization of variable rc
scsi: mpt3sas: Fix memset() in non-RDPQ mode
scsi: iscsi: Fix reference count leak in iscsi_boot_create_kobj
... -
Pull i2c updates from Wolfram Sang:
"I2C has quite some patches for you this time. I hope it is the move to
per-driver-maintainers which is now showing results. We will see.The big news is two new drivers (Nuvoton NPCM and Qualcomm CCI),
larger refactoring of the Designware, Tegra, and PXA drivers, the
Cadence driver supports being a slave now, and there is support to
instanciate SPD eeproms for well-known cases (which will be
user-visible because the i801 driver supports it), and some
devm_platform_ioremap_resource() conversions which blow up the
diffstat.Note that I applied the Nuvoton driver quite late, so some minor fixup
patches arrived during the merge window. I chose to apply them right
away because they were trivial"* 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (109 commits)
i2c: Drop stray comma in MODULE_AUTHOR statements
i2c: npcm7xx: npcm_i2caddr[] can be static
MAINTAINERS: npcm7xx: Add maintainer for Nuvoton NPCM BMC
i2c: npcm7xx: Fix a couple of error codes in probe
i2c: icy: Fix build with CONFIG_AMIGA_PCMCIA=n
i2c: npcm7xx: Remove unnecessary parentheses
i2c: npcm7xx: Add support for slave mode for Nuvoton
i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver
dt-bindings: i2c: npcm7xx: add NPCM I2C controller
i2c: pxa: don't error out if there's no pinctrl
i2c: add 'single-master' property to generic bindings
i2c: designware: Add Baikal-T1 System I2C support
i2c: designware: Move reg-space remapping into a dedicated function
i2c: designware: Retrieve quirk flags as early as possible
i2c: designware: Convert driver to using regmap API
i2c: designware: Discard Cherry Trail model flag
i2c: designware: Add Baytrail sem config DW I2C platform dependency
i2c: designware: slave: Set DW I2C core module dependency
i2c: designware: Use `-y` to build multi-object modules
dt-bindings: i2c: dw: Add Baikal-T1 SoC I2C controller
... -
Pull more media updates from Mauro Carvalho Chehab:
- a set of atomisp patches. They remove several abstraction layers, and
fixes clang and gcc warnings (that were hidden via some macros that
were disabling 4 or 5 types of warnings there). There are also some
important fixes and sensor auto-detection on newer BIOSes via ACPI
_DCM tables.- some fixes
* tag 'media/v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (95 commits)
media: rkvdec: Fix H264 scaling list order
media: v4l2-ctrls: Unset correct HEVC loop filter flag
media: videobuf2-dma-contig: fix bad kfree in vb2_dma_contig_clear_max_seg_size
media: v4l2-subdev.rst: correct information about v4l2 events
media: s5p-mfc: Properly handle dma_parms for the allocated devices
media: medium: cec: Make MEDIA_CEC_SUPPORT default to n if !MEDIA_SUPPORT
media: cedrus: Implement runtime PM
media: cedrus: Program output format during each run
media: atomisp: improve ACPI/DMI detection logs
media: Revert "media: atomisp: add Asus Transform T101HA ACPI vars"
media: Revert "media: atomisp: Add some ACPI detection info"
media: atomisp: improve sensor detection code to use _DSM table
media: atomisp: get rid of an iomem abstraction layer
media: atomisp: get rid of a string_support.h abstraction layer
media: atomisp: use strscpy() instead of less secure variants
media: atomisp: set DFS to MAX if sensor doesn't report fps
media: atomisp: use different dfs failed messages
media: atomisp: change the detection of ISP2401 at runtime
media: atomisp: use macros from intel-family.h
media: atomisp: don't set hpll_freq twice with different values
... -
Pull libnvdimm updates from Dan Williams:
"Small collection of cleanups to rework usage of ->queuedata and the
GUID api"* tag 'libnvdimm-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
nvdimm/pmem: stop using ->queuedata
nvdimm/btt: stop using ->queuedata
nvdimm/blk: stop using ->queuedata
libnvdimm: Replace guid_copy() with import_guid() where it makes sense -
Let's keep "git status" happy and quiet.
Fixes: f5b5a164f9a1 ("Add sample notification program")
Signed-off-by: Linus Torvalds -
Pull iomap fix from Darrick Wong:
"A single iomap bug fix for a variable type mistake on 32-bit
architectures, fixing an integer overflow problem in the unshare
actor"* tag 'iomap-5.8-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
iomap: Fix unsharing of an extent >2GB on a 32-bit machine -
Pull xfs fix from Darrick Wong:
"We've settled down into the bugfix phase; this one fixes a resource
leak on an error bailout path"* tag 'xfs-5.8-merge-9' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: Add the missed xfs_perag_put() for xfs_ifree_cluster() -
Pull 9p update from Dominique Martinet:
"Another very quiet cycle... Only one commit: increase the size of the
ring used for xen transport"* tag '9p-for-5.8' of git://github.com/martinetd/linux:
9p/xen: increase XEN_9PFS_RING_ORDER -
Pull powerpc fix from Michael Ellerman:
"One fix for a recent change which broke nested KVM guests on Power9.Thanks to Alexey Kardashevskiy"
* tag 'powerpc-5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
KVM: PPC: Fix nested guest RC bits update -
Pull ARM fixes from Russell King:
- fix for "hex" Kconfig default to use 0x0 rather than 0 to allow these
to be removed from defconfigs- fix from Ard Biesheuvel for EFI HYP mode booting
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully
ARM: 8984/1: Kconfig: set default ZBOOT_ROM_TEXT/BSS value to 0x0 -
Pull OpenRISC update from Stafford Horne:
"One patch found wile I was getting the glibc port ready: fix issue
with clone TLS arg getting overwritten"* tag 'for-linus' of git://github.com/openrisc/linux:
openrisc: Fix issue with argument clobbering for clone/fork -
Pull alpha updates from Matt Turner:
"A few changes for alpha. They're mostly small janitorial fixes but
there's also a build fix and most notably a patch from Mikulas that
fixes a hang on boot on the Avanti platform, which required quite a
bit of work and review"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha:
alpha: Fix build around srm_sysrq_reboot_op
alpha: c_next should increase position index
alpha: Replace sg++ with sg = sg_next(sg)
alpha: fix memory barriers so that they conform to the specification
alpha: remove unneeded semicolon in sys_eiger.c
alpha: remove unneeded semicolon in osf_sys.c
alpha: Replace strncmp with str_has_prefix
alpha: fix rtc port ranges
alpha: Kconfig: pedantic formatting -
Pull x86 RAS updates from Thomas Gleixner:
"RAS updates from Borislav Petkov:- Unmap a whole guest page if an MCE is encountered in it to avoid
follow-on MCEs leading to the guest crashing, by Tony Luck.This change collided with the entry changes and the merge
resolution would have been rather unpleasant. To avoid that the
entry branch was merged in before applying this. The resulting code
did not change over the rebase.- AMD MCE error thresholding machinery cleanup and hotplug
sanitization, by Thomas Gleixner.- Change the MCE notifiers to denote whether they have handled the
error and not break the chain early by returning NOTIFY_STOP, thus
giving the opportunity for the later handlers in the chain to see
it. By Tony Luck.- Add AMD family 0x17, models 0x60-6f support, by Alexander Monakov.
- Last but not least, the usual round of fixes and improvements"
* tag 'ras-core-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/mce/dev-mcelog: Fix -Wstringop-truncation warning about strncpy()
x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned
EDAC/amd64: Add AMD family 17h model 60h PCI IDs
hwmon: (k10temp) Add AMD family 17h model 60h PCI match
x86/amd_nb: Add AMD family 17h model 60h PCI IDs
x86/mcelog: Add compat_ioctl for 32-bit mcelog support
x86/mce: Drop bogus comment about mce.kflags
x86/mce: Fixup exception only for the correct MCEs
EDAC: Drop the EDAC report status checks
x86/mce: Add mce=print_all option
x86/mce: Change default MCE logger to check mce->kflags
x86/mce: Fix all mce notifiers to update the mce->kflags bitmask
x86/mce: Add a struct mce.kflags field
x86/mce: Convert the CEC to use the MCE notifier
x86/mce: Rename "first" function as "early"
x86/mce/amd, edac: Remove report_gart_errors
x86/mce/amd: Make threshold bank setting hotplug robust
x86/mce/amd: Cleanup threshold device remove path
x86/mce/amd: Straighten CPU hotplug path
x86/mce/amd: Sanitize thresholding device creation hotplug path
... -
Pull x86 entry updates from Thomas Gleixner:
"The x86 entry, exception and interrupt code reworkThis all started about 6 month ago with the attempt to move the Posix
CPU timer heavy lifting out of the timer interrupt code and just have
lockless quick checks in that code path. Trivial 5 patches.This unearthed an inconsistency in the KVM handling of task work and
the review requested to move all of this into generic code so other
architectures can share.Valid request and solved with another 25 patches but those unearthed
inconsistencies vs. RCU and instrumentation.Digging into this made it obvious that there are quite some
inconsistencies vs. instrumentation in general. The int3 text poke
handling in particular was completely unprotected and with the batched
update of trace events even more likely to expose to endless int3
recursion.In parallel the RCU implications of instrumenting fragile entry code
came up in several discussions.The conclusion of the x86 maintainer team was to go all the way and
make the protection against any form of instrumentation of fragile and
dangerous code pathes enforcable and verifiable by tooling.A first batch of preparatory work hit mainline with commit
d5f744f9a2ac ("Pull x86 entry code updates from Thomas Gleixner")That (almost) full solution introduced a new code section
'.noinstr.text' into which all code which needs to be protected from
instrumentation of all sorts goes into. Any call into instrumentable
code out of this section has to be annotated. objtool has support to
validate this.Kprobes now excludes this section fully which also prevents BPF from
fiddling with it and all 'noinstr' annotated functions also keep
ftrace off. The section, kprobes and objtool changes are already
merged.The major changes coming with this are:
- Preparatory cleanups
- Annotating of relevant functions to move them into the
noinstr.text section or enforcing inlining by marking them
__always_inline so the compiler cannot misplace or instrument
them.- Splitting and simplifying the idtentry macro maze so that it is
now clearly separated into simple exception entries and the more
interesting ones which use interrupt stacks and have the paranoid
handling vs. CR3 and GS.- Move quite some of the low level ASM functionality into C code:
- enter_from and exit to user space handling. The ASM code now
calls into C after doing the really necessary ASM handling and
the return path goes back out without bells and whistels in
ASM.- exception entry/exit got the equivivalent treatment
- move all IRQ tracepoints from ASM to C so they can be placed as
appropriate which is especially important for the int3
recursion issue.- Consolidate the declaration and definition of entry points between
32 and 64 bit. They share a common header and macros now.- Remove the extra device interrupt entry maze and just use the
regular exception entry code.- All ASM entry points except NMI are now generated from the shared
header file and the corresponding macros in the 32 and 64 bit
entry ASM.- The C code entry points are consolidated as well with the help of
DEFINE_IDTENTRY*() macros. This allows to ensure at one central
point that all corresponding entry points share the same
semantics. The actual function body for most entry points is in an
instrumentable and sane state.There are special macros for the more sensitive entry points, e.g.
INT3 and of course the nasty paranoid #NMI, #MCE, #DB and #DF.
They allow to put the whole entry instrumentation and RCU handling
into safe places instead of the previous pray that it is correct
approach.- The INT3 text poke handling is now completely isolated and the
recursion issue banned. Aside of the entry rework this required
other isolation work, e.g. the ability to force inline bsearch.- Prevent #DB on fragile entry code, entry relevant memory and
disable it on NMI, #MC entry, which allowed to get rid of the
nested #DB IST stack shifting hackery.- A few other cleanups and enhancements which have been made
possible through this and already merged changes, e.g.
consolidating and further restricting the IDT code so the IDT
table becomes RO after init which removes yet another popular
attack vector- About 680 lines of ASM maze are gone.
There are a few open issues:
- An escape out of the noinstr section in the MCE handler which needs
some more thought but under the aspect that MCE is a complete
trainwreck by design and the propability to survive it is low, this
was not high on the priority list.- Paravirtualization
When PV is enabled then objtool complains about a bunch of indirect
calls out of the noinstr section. There are a few straight forward
ways to fix this, but the other issues vs. general correctness were
more pressing than parawitz.- KVM
KVM is inconsistent as well. Patches have been posted, but they
have not yet been commented on or picked up by the KVM folks.- IDLE
Pretty much the same problems can be found in the low level idle
code especially the parts where RCU stopped watching. This was
beyond the scope of the more obvious and exposable problems and is
on the todo list.The lesson learned from this brain melting exercise to morph the
evolved code base into something which can be validated and understood
is that once again the violation of the most important engineering
principle "correctness first" has caused quite a few people to spend
valuable time on problems which could have been avoided in the first
place. The "features first" tinkering mindset really has to stop.With that I want to say thanks to everyone involved in contributing to
this effort. Special thanks go to the following people (alphabetical
order): Alexandre Chartre, Andy Lutomirski, Borislav Petkov, Brian
Gerst, Frederic Weisbecker, Josh Poimboeuf, Juergen Gross, Lai
Jiangshan, Macro Elver, Paolo Bonzin,i Paul McKenney, Peter Zijlstra,
Vitaly Kuznetsov, and Will Deacon"* tag 'x86-entry-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (142 commits)
x86/entry: Force rcu_irq_enter() when in idle task
x86/entry: Make NMI use IDTENTRY_RAW
x86/entry: Treat BUG/WARN as NMI-like entries
x86/entry: Unbreak __irqentry_text_start/end magic
x86/entry: __always_inline CR2 for noinstr
lockdep: __always_inline more for noinstr
x86/entry: Re-order #DB handler to avoid *SAN instrumentation
x86/entry: __always_inline arch_atomic_* for noinstr
x86/entry: __always_inline irqflags for noinstr
x86/entry: __always_inline debugreg for noinstr
x86/idt: Consolidate idt functionality
x86/idt: Cleanup trap_init()
x86/idt: Use proper constants for table size
x86/idt: Add comments about early #PF handling
x86/idt: Mark init only functions __init
x86/entry: Rename trace_hardirqs_off_prepare()
x86/entry: Clarify irq_{enter,exit}_rcu()
x86/entry: Remove DBn stacks
x86/entry: Remove debug IDT frobbing
x86/entry: Optimize local_db_save() for virt
... -
Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'In order to convert all of them to 1 tab + 'help', I ran the
following commend:$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada
