- 09 Dec, 2020 5 commits
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Peter Zijlstra authored
One copy of this logic is better than three. Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20201207090243.GE3040@hirez.programming.kicks-ass.net
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Peter Zijlstra authored
All users of rwsem_read_trylock() do rwsem_set_reader_owned(sem) on success, move it into rwsem_read_trylock() proper. Signed-off-by:
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Peter Zijlstra authored
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Eric W. Biederman authored
In preparation for converting exec_update_mutex to a rwsem so that multiple readers can execute in parallel and not deadlock, add down_read_interruptible. This is needed for perf_event_open to be converted (with no semantic changes) from working on a mutex to wroking on a rwsem. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Signed-off-by:
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Eric W. Biederman authored
In preparation for converting exec_update_mutex to a rwsem so that multiple readers can execute in parallel and not deadlock, add down_read_killable_nested. This is needed so that kcmp_lock can be converted from working on a mutexes to working on rw_semaphores. Signed-off-by:
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- 03 Dec, 2020 9 commits
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Mauro Carvalho Chehab authored
The kernel-doc markup is wrong: it is asking the tool to document struct refcount_struct, instead of documenting typedef refcount_t. Signed-off-by:
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by:
Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/afb9bb1e675bf5f72a34a55d780779d7d5916b4c.1606823973.git.mchehab+huawei@kernel.org
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Mauro Carvalho Chehab authored
Changeset cd8084f9 ("locking/lockdep: Apply crossrelease to completions") added a CONFIG_LOCKDEP_COMPLETE (that was later renamed to CONFIG_LOCKDEP_COMPLETIONS). Such changeset renamed the init_completion, and add a macro that would either run a modified version or the original code. However, such code reported too many false positives. So, it ended being dropped later on by changeset e966eaee ("locking/lockdep: Remove the cross-release locking checks"). Yet, the define remained there as just: #define init_completion(x) __init_completion(x) Get rid of the define, and return __init_completion() function to its original name. Fixes: e966eaee ("locking/lockdep: Remove the cross-release locking checks") Signed-off-by:
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Peter Zijlstra authored
Update the files list to include refcount.h and the Documentation/ Signed-off-by: -
Peter Zijlstra authored
It's been superseded by Documentation/atomic_*.txt. Signed-off-by: -
Peter Zijlstra authored
More consistent naming should make it easier to untangle the _Generic token pasting maze called __seqprop(). Signed-off-by:
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Boqun Feng authored
Add a self test case to test the behavior for the following case: lock(A); lock_nest_lock(C1, A); lock(B); lock_nest_lock(C2, A); This is a reproducer for a problem[1] reported by Chris Wilson, and is helpful to prevent this. [1]: https://lore.kernel.org/lkml/160390684819.31966.12048967113267928793@build.alporthouse.com/Signed-off-by:
Boqun Feng <boqun.feng@gmail.com> Signed-off-by:
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Peter Zijlstra authored
The selftest nests rwlock_t inside raw_spinlock_t, this is invalid. Reported-by:
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Arnd Bergmann authored
When building with W=2, there is a flood of warnings about the seqlock macros shadowing local variables: 19806 linux/seqlock.h:331:11: warning: declaration of 'seq' shadows a previous local [-Wshadow] 48 linux/seqlock.h:348:11: warning: declaration of 'seq' shadows a previous local [-Wshadow] 8 linux/seqlock.h:379:11: warning: declaration of 'seq' shadows a previous local [-Wshadow] Prefix the local variables to make the warning useful elsewhere again. Fixes: 52ac39e5 ("seqlock: seqcount_t: Implement all read APIs as statement expressions") Signed-off-by:Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2Linus Torvalds authored
Pull gfs2 fixes from Andreas Gruenbacher: "Various gfs2 fixes" * tag 'gfs2-v5.10-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: gfs2: Fix deadlock between gfs2_{create_inode,inode_lookup} and delete_work_func gfs2: Upgrade shared glocks for atime updates gfs2: Don't freeze the file system during unmount gfs2: check for empty rgrp tree in gfs2_ri_update gfs2: set lockdep subclass for iopen glocks gfs2: Fix deadlock dumping resource group glocks
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- 02 Dec, 2020 6 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linuxLinus Torvalds authored
Pull arm64 fixes from Will Deacon: "I'm sad to say that we've got an unusually large arm64 fixes pull for rc7 which addresses numerous significant instrumentation issues with our entry code. Without these patches, lockdep is hopelessly unreliable in some configurations [1,2] and syzkaller is therefore not a lot of use because it's so noisy. Although much of this has always been broken, it appears to have been exposed more readily by other changes such as 044d0d6d ("lockdep: Only trace IRQ edges") and general lockdep improvements around IRQ tracing and NMIs. Fixing this properly required moving much of the instrumentation hooks from our entry assembly into C, which Mark has been working on for the last few weeks. We're not quite ready to move to the recently added generic functions yet, but the code here has been deliberately written to mimic that closely so we can look at cleaning things up once we have a bit more breathing room. Having said all that, the second version of these patches was posted last week and I pushed it into our CI (kernelci and cki) along with a commit which forced on PROVE_LOCKING, NOHZ_FULL and CONTEXT_TRACKING_FORCE. The result? We found a real bug in the md/raid10 code [3]. Oh, and there's also a really silly typo patch that's unrelated. Summary: - Fix numerous issues with instrumentation and exception entry - Fix hideous typo in unused register field definition" [1] https://lore.kernel.org/r/CACT4Y+aAzoJ48Mh1wNYD17pJqyEcDnrxGfApir=-j171TnQXhw@mail.gmail.com [2] https://lore.kernel.org/r/20201119193819.GA2601289@elver.google.com [3] https://lore.kernel.org/r/94c76d5e-466a-bc5f-e6c2-a11b65c39f83@redhat.com * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: mte: Fix typo in macro definition arm64: entry: fix EL1 debug transitions arm64: entry: fix NMI {user, kernel}->kernel transitions arm64: entry: fix non-NMI kernel<->kernel transitions arm64: ptrace: prepare for EL1 irq/rcu tracking arm64: entry: fix non-NMI user<->kernel transitions arm64: entry: move el1 irq/nmi logic to C arm64: entry: prepare ret_to_user for function call arm64: entry: move enter_from_user_mode to entry-common.c arm64: entry: mark entry code as noinstr arm64: mark idle code as noinstr arm64: syscall: exit userspace before unmasking exceptions
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git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds authored
Pull vdpa fixes from Michael Tsirkin: "A couple of fixes that surfaced at the last minute" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost_vdpa: return -EFAULT if copy_to_user() fails vdpa: mlx5: fix vdpa/vhost dependencies
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/soundLinus Torvalds authored
Pull sound fixes from Takashi Iwai: "Here are the pending sound fixes for 5.10: all small device-specific fixes, and nothing particular stands out, so far" * tag 'sound-5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ALSA: hda/realtek: Add mute LED quirk to yet another HP x360 model ALSA: hda/realtek: Fix bass speaker DAC assignment on Asus Zephyrus G14 ALSA: hda/generic: Add option to enforce preferred_dacs pairs ALSA: usb-audio: US16x08: fix value count for level meters ALSA: hda/realtek - Add new codec supported for ALC897 ASoC: rt5682: change SAR voltage threshold ASoC: wm_adsp: fix error return code in wm_adsp_load() ALSA: hda/realtek: Enable headset of ASUS UX482EG & B9400CEA with ALC294 ASoC: qcom: Fix enabling BCLK and LRCLK in LPAIF invalid state ALSA: hda/realtek - Fixed Dell AIO wrong sound tone ASoC: Intel: bytcr_rt5640: Fix HP Pavilion x2 Detachable quirks
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Linus Torvalds authored
Merge tag 'trace-v5.10-rc6-bootconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull bootconfig fixes from Steven Rostedt: "Have bootconfig size and checksum be little endian In case the bootconfig is created on one kind of endian machine, and then read on the other kind of endian kernel, the size and checksum will be incorrect. Instead, have both the size and checksum always be little endian and have the tool and the kernel convert it from little endian to or from the host endian" * tag 'trace-v5.10-rc6-bootconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: docs: bootconfig: Add the endianness of fields tools/bootconfig: Store size and checksum in footer as le32 bootconfig: Load size and checksum in the footer as le32
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Dan Carpenter authored
The copy_to_user() function returns the number of bytes remaining to be copied but this should return -EFAULT to the user. Fixes: 1b48dc03 ("vhost: vdpa: report iova range") Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Link: https://lore.kernel.org/r/X8c32z5EtDsMyyIL@mwandaSigned-off-by:
Michael S. Tsirkin <mst@redhat.com> Acked-by:
Jason Wang <jasowang@redhat.com> Reviewed-by:
Stefano Garzarella <sgarzare@redhat.com>
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Randy Dunlap authored
drivers/vdpa/mlx5/ uses vhost_iotlb*() interfaces, so select VHOST_IOTLB to make them be built. However, if VHOST_IOTLB is the only VHOST symbol that is set/enabled, the object file still won't be built because drivers/Makefile won't descend into drivers/vhost/ to build it, so make drivers/Makefile build the needed binary whenever VHOST_IOTLB is set, like it does for VHOST_RING. Fixes these build errors: ERROR: modpost: "vhost_iotlb_itree_next" [drivers/vdpa/mlx5/mlx5_vdpa.ko] undefined! ERROR: modpost: "vhost_iotlb_itree_first" [drivers/vdpa/mlx5/mlx5_vdpa.ko] undefined! Fixes: 29064bfd ("vdpa/mlx5: Add support library for mlx5 VDPA implementation") Fixes: aff90770 ("vdpa/mlx5: Fix dependency on MLX5_CORE") Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Randy Dunlap <rdunlap@infradead.org> Cc: Eli Cohen <eli@mellanox.com> Cc: Parav Pandit <parav@mellanox.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: virtualization@lists.linux-foundation.org Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: netdev@vger.kernel.org Link: https://lore.kernel.org/r/20201128213905.27409-1-rdunlap@infradead.orgSigned-off-by:
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- 01 Dec, 2020 12 commits
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git://git.samba.org/sfrench/cifs-2.6Linus Torvalds authored
Pull cifs fixes from Steve French: "Two smb3 fixes for stable" * tag '5.10-rc6-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: fix potential use-after-free in cifs_echo_request() cifs: allow syscalls to be restarted in __smb_send_rqst()
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-traceLinus Torvalds authored
Pull tracing fixes from Steven Rostedt: - Use correct timestamp variable for ring buffer write stamp update - Fix up before stamp and write stamp when crossing ring buffer sub buffers - Keep a zero delta in ring buffer in slow path if cmpxchg fails - Fix trace_printk static buffer for archs that care - Fix ftrace record accounting for ftrace ops with trampolines - Fix DYNAMIC_FTRACE_WITH_DIRECT_CALLS dependency - Remove WARN_ON in hwlat tracer that triggers on something that is OK - Make "my_tramp" trampoline in ftrace direct sample code global - Fixes in the bootconfig tool for better alignment management * tag 'trace-v5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ring-buffer: Always check to put back before stamp when crossing pages ftrace: Fix DYNAMIC_FTRACE_WITH_DIRECT_CALLS dependency ftrace: Fix updating FTRACE_FL_TRAMP tracing: Fix alignment of static buffer tracing: Remove WARN_ON in start_thread() samples/ftrace: Mark my_tramp[12]? global ring-buffer: Set the right timestamp in the slow path of __rb_reserve_next() ring-buffer: Update write stamp with the correct ts docs: bootconfig: Update file format on initrd image tools/bootconfig: Align the bootconfig applied initrd image size to 4 tools/bootconfig: Fix to check the write failure correctly tools/bootconfig: Fix errno reference after printf()
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git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds authored
Pull vhost fixes from Michael Tsirkin: "A couple of minor fixes" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost-vdpa: fix page pinning leakage in error path (rework) vringh: fix vringh_iov_push_*() documentation vhost scsi: fix lun reset completion handling
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Masami Hiramatsu authored
Add a description about the endianness of the size and the checksum fields. Those must be stored as le32 instead of u32. This will allow us to apply bootconfig to the cross build initrd without caring the endianness. Link: https://lkml.kernel.org/r/160583936246.547349.10964204130590955409.stgit@devnote2Reported-by:
Steven Rostedt <rostedt@goodmis.org> Suggested-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
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Masami Hiramatsu authored
Store the size and the checksum fields in the footer as le32 instead of u32. This will allow us to apply bootconfig to the cross build initrd without caring the endianness. Link: https://lkml.kernel.org/r/160583935332.547349.5897811300636587426.stgit@devnote2Reported-by:
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Masami Hiramatsu authored
Load the size and the checksum fields in the footer as le32 instead of u32. This will allow us to apply bootconfig to the cross build initrd without caring the endianness. Link: https://lkml.kernel.org/r/160583934457.547349.10504070298990791074.stgit@devnote2Reported-by:
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Steven Rostedt (VMware) authored
The current ring buffer logic checks to see if the updating of the event buffer was interrupted, and if it is, it will try to fix up the before stamp with the write stamp to make them equal again. This logic is flawed, because if it is not interrupted, the two are guaranteed to be different, as the current event just updated the before stamp before allocation. This guarantees that the next event (this one or another interrupting one) will think it interrupted the time updates of a previous event and inject an absolute time stamp to compensate. The correct logic is to always update the timestamps when traversing to a new sub buffer. Cc: stable@vger.kernel.org Fixes: a389d86f ("ring-buffer: Have nested events still record running time stamp") Signed-off-by:
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Naveen N. Rao authored
DYNAMIC_FTRACE_WITH_DIRECT_CALLS should depend on DYNAMIC_FTRACE_WITH_REGS since we need ftrace_regs_caller(). Link: https://lkml.kernel.org/r/fc4b257ea8689a36f086d2389a9ed989496ca63a.1606412433.git.naveen.n.rao@linux.vnet.ibm.com Cc: stable@vger.kernel.org Fixes: 763e34e7 ("ftrace: Add register_ftrace_direct()") Signed-off-by:
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by:
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Naveen N. Rao authored
On powerpc, kprobe-direct.tc triggered FTRACE_WARN_ON() in ftrace_get_addr_new() followed by the below message: Bad trampoline accounting at: 000000004222522f (wake_up_process+0xc/0x20) (f0000001) The set of steps leading to this involved: - modprobe ftrace-direct-too - enable_probe - modprobe ftrace-direct - rmmod ftrace-direct <-- trigger The problem turned out to be that we were not updating flags in the ftrace record properly. From the above message about the trampoline accounting being bad, it can be seen that the ftrace record still has FTRACE_FL_TRAMP set though ftrace-direct module is going away. This happens because we are checking if any ftrace_ops has the FTRACE_FL_TRAMP flag set _before_ updating the filter hash. The fix for this is to look for any _other_ ftrace_ops that also needs FTRACE_FL_TRAMP. Link: https://lkml.kernel.org/r/56c113aa9c3e10c19144a36d9684c7882bf09af5.1606412433.git.naveen.n.rao@linux.vnet.ibm.com Cc: stable@vger.kernel.org Fixes: a124692b ("ftrace: Enable trampoline when rec count returns back to one") Signed-off-by:
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Minchan Kim authored
With 5.9 kernel on ARM64, I found ftrace_dump output was broken but it had no problem with normal output "cat /sys/kernel/debug/tracing/trace". With investigation, it seems coping the data into temporal buffer seems to break the align binary printf expects if the static buffer is not aligned with 4-byte. IIUC, get_arg in bstr_printf expects that args has already right align to be decoded and seq_buf_bprintf says ``the arguments are saved in a 32bit word array that is defined by the format string constraints``. So if we don't keep the align under copy to temporal buffer, the output will be broken by shifting some bytes. This patch fixes it. Link: https://lkml.kernel.org/r/20201125225654.1618966-1-minchan@kernel.org Cc: <stable@vger.kernel.org> Fixes: 8e99cf91 ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic") Signed-off-by:
Namhyung Kim <namhyung@kernel.org> Signed-off-by:
Minchan Kim <minchan@kernel.org> Signed-off-by:
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Vasily Averin authored
This patch reverts commit 978defee ("tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists") .start hook can be legally called several times if according tracer is stopped screen window 1 [root@localhost ~]# echo 1 > /sys/kernel/tracing/events/kmem/kfree/enable [root@localhost ~]# echo 1 > /sys/kernel/tracing/options/pause-on-trace [root@localhost ~]# less -F /sys/kernel/tracing/trace screen window 2 [root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on 0 [root@localhost ~]# echo hwlat > /sys/kernel/debug/tracing/current_tracer [root@localhost ~]# echo 1 > /sys/kernel/debug/tracing/tracing_on [root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on 0 [root@localhost ~]# echo 2 > /sys/kernel/debug/tracing/tracing_on triggers warning in dmesg: WARNING: CPU: 3 PID: 1403 at kernel/trace/trace_hwlat.c:371 hwlat_tracer_start+0xc9/0xd0 Link: https://lkml.kernel.org/r/bd4d3e70-400d-9c82-7b73-a2d695e86b58@virtuozzo.com Cc: Ingo Molnar <mingo@redhat.com> Cc: stable@vger.kernel.org Fixes: 978defee ("tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists") Signed-off-by:
Vasily Averin <vvs@virtuozzo.com> Signed-off-by:
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Sami Tolvanen authored
my_tramp[12]? are declared as global functions in C, but they are not marked global in the inline assembly definition. This mismatch confuses Clang's Control-Flow Integrity checking. Fix the definitions by adding .globl. Link: https://lkml.kernel.org/r/20201113183414.1446671-1-samitolvanen@google.com Fixes: 9d907f1a ("ftrace/samples: Add a sample module that implements modify_ftrace_direct()") Reviewed-by:
Sami Tolvanen <samitolvanen@google.com> Signed-off-by:
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- 30 Nov, 2020 8 commits
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Andreas Gruenbacher authored
In gfs2_create_inode and gfs2_inode_lookup, make sure to cancel any pending delete work before taking the inode glock. Otherwise, gfs2_cancel_delete_work may block waiting for delete_work_func to complete, and delete_work_func may block trying to acquire the inode glock in gfs2_inode_lookup. Reported-by:
Alexander Aring <aahringo@redhat.com> Fixes: a0e3cc65 ("gfs2: Turn gl_delete into a delayed work") Cc: stable@vger.kernel.org # v5.8+ Signed-off-by:
Andreas Gruenbacher <agruenba@redhat.com>
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Paulo Alcantara authored
This patch fixes a potential use-after-free bug in cifs_echo_request(). For instance, thread 1 -------- cifs_demultiplex_thread() clean_demultiplex_info() kfree(server) thread 2 (workqueue) -------- apic_timer_interrupt() smp_apic_timer_interrupt() irq_exit() __do_softirq() run_timer_softirq() call_timer_fn() cifs_echo_request() <- use-after-free in server ptr Signed-off-by:Paulo Alcantara (SUSE) <pc@cjr.nz> CC: Stable <stable@vger.kernel.org> Reviewed-by:
Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by:
Steve French <stfrench@microsoft.com>
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Paulo Alcantara authored
A customer has reported that several files in their multi-threaded app were left with size of 0 because most of the read(2) calls returned -EINTR and they assumed no bytes were read. Obviously, they could have fixed it by simply retrying on -EINTR. We noticed that most of the -EINTR on read(2) were due to real-time signals sent by glibc to process wide credential changes (SIGRT_1), and its signal handler had been established with SA_RESTART, in which case those calls could have been automatically restarted by the kernel. Let the kernel decide to whether or not restart the syscalls when there is a signal pending in __smb_send_rqst() by returning -ERESTARTSYS. If it can't, it will return -EINTR anyway. Signed-off-by:
Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by:
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Andrea Righi authored
In the slow path of __rb_reserve_next() a nested event(s) can happen between evaluating the timestamp delta of the current event and updating write_stamp via local_cmpxchg(); in this case the delta is not valid anymore and it should be set to 0 (same timestamp as the interrupting event), since the event that we are currently processing is not the last event in the buffer. Link: https://lkml.kernel.org/r/X8IVJcp1gRE+FJCJ@xps-13-7390 Cc: Ingo Molnar <mingo@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Link: https://lwn.net/Articles/831207 Fixes: a389d86f ("ring-buffer: Have nested events still record running time stamp") Signed-off-by:
Andrea Righi <andrea.righi@canonical.com> Signed-off-by:
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Steven Rostedt (VMware) authored
The write stamp, used to calculate deltas between events, was updated with the stale "ts" value in the "info" structure, and not with the updated "ts" variable. This caused the deltas between events to be inaccurate, and when crossing into a new sub buffer, had time go backwards. Link: https://lkml.kernel.org/r/20201124223917.795844-1-elavila@google.com Cc: stable@vger.kernel.org Fixes: a389d86f ("ring-buffer: Have nested events still record running time stamp") Reported-by:
"J. Avila" <elavila@google.com> Tested-by:
Daniel Mentz <danielmentz@google.com> Tested-by:
Will McVicker <willmcvicker@google.com> Signed-off-by:
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Vincenzo Frascino authored
UL in the definition of SYS_TFSR_EL1_TF1 was misspelled causing compilation issues when trying to implement in kernel MTE async mode. Fix the macro correcting the typo. Note: MTE async mode will be introduced with a future series. Fixes: c058b1c4 ("arm64: mte: system register definitions") Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by:
Vincenzo Frascino <vincenzo.frascino@arm.com> Acked-by:
Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20201130170709.22309-1-vincenzo.frascino@arm.comSigned-off-by:
Will Deacon <will@kernel.org>
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Mark Rutland authored
In debug_exception_enter() and debug_exception_exit() we trace hardirqs on/off while RCU isn't guaranteed to be watching, and we don't save and restore the hardirq state, and so may return with this having changed. Handle this appropriately with new entry/exit helpers which do the bare minimum to ensure this is appropriately maintained, without marking debug exceptions as NMIs. These are placed in entry-common.c with the other entry/exit helpers. In future we'll want to reconsider whether some debug exceptions should be NMIs, but this will require a significant refactoring, and for now this should prevent issues with lockdep and RCU. Signed-off-by:
Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marins <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20201130115950.22492-12-mark.rutland@arm.comSigned-off-by:
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Mark Rutland authored
Exceptions which can be taken at (almost) any time are consdiered to be NMIs. On arm64 that includes: * SDEI events * GICv3 Pseudo-NMIs * Kernel stack overflows * Unexpected/unhandled exceptions ... but currently debug exceptions (BRKs, breakpoints, watchpoints, single-step) are not considered NMIs. As these can be taken at any time, kernel features (lockdep, RCU, ftrace) may not be in a consistent kernel state. For example, we may take an NMI from the idle code or partway through an entry/exit path. While nmi_enter() and nmi_exit() handle most of this state, notably they don't save/restore the lockdep state across an NMI being taken and handled. When interrupts are enabled and an NMI is taken, lockdep may see interrupts become disabled within the NMI code, but not see interrupts become enabled when returning from the NMI, leaving lockdep believing interrupts are disabled when they are actually disabled. The x86 code handles this in idtentry_{enter,exit}_nmi(), which will shortly be moved to the generic entry code. As we can't use either yet, we copy the x86 approach in arm64-specific helpers. All the NMI entrypoints are marked as noinstr to prevent any instrumentation handling code being invoked before the state has been corrected. Signed-off-by:
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