Spin-waiting on the control CPU until the AP reaches the TSC
synchronization is just a waste especially in the case that there is no
synchronization required.
As the synchronization has to run with interrupts disabled the control CPU
part can just be done from a SMP function call. The upcoming AP issues that
call async only in the case that synchronization is required.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.148255496@linutronix.de
There are four logical parts to what native_cpu_up() does on the BSP (or
on the controlling CPU for a later hotplug):
1) Wake the AP by sending the INIT/SIPI/SIPI sequence.
2) Wait for the AP to make it as far as wait_for_master_cpu() which
sets that CPU's bit in cpu_initialized_mask, then sets the bit in
cpu_callout_mask to let the AP proceed through cpu_init().
3) Wait for the AP to finish cpu_init() and get as far as the
smp_callin() call, which sets that CPU's bit in cpu_callin_mask.
4) Perform the TSC synchronization and wait for the AP to actually
mark itself online in cpu_online_mask.
In preparation to allow these phases to operate in parallel on multiple
APs, split them out into separate functions and document the interactions
a little more clearly in both the BP and AP code paths.
No functional change intended.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.928917242@linutronix.de
Peter stumbled over the barrier() after the invocation of smp_callin() in
start_secondary():
"...this barrier() and it's comment seem weird vs smp_callin(). That
function ends with an atomic bitop (it has to, at the very least it must
not be weaker than store-release) but also has an explicit wmb() to order
setup vs CPU_STARTING.
There is no way the smp_processor_id() referred to in this comment can land
before cpu_init() even without the barrier()."
The barrier() along with the comment was added in 2003 with commit
d8f19f2cac70 ("[PATCH] x86-64 merge") in the history tree. One of those
well documented combo patches of that time which changes world and some
more. The context back then was:
/*
* Dont put anything before smp_callin(), SMP
* booting is too fragile that we want to limit the
* things done here to the most necessary things.
*/
cpu_init();
smp_callin();
+ /* otherwise gcc will move up smp_processor_id before the cpu_init */
+ barrier();
Dprintk("cpu %d: waiting for commence\n", smp_processor_id());
Even back in 2003 the compiler was not allowed to reorder that
smp_processor_id() invocation before the cpu_init() function call.
Especially not as smp_processor_id() resolved to:
asm volatile("movl %%gs:%c1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory");
There is no trace of this change in any mailing list archive including the
back then official x86_64 list discuss@x86-64.org, which would explain the
problem this change solved.
The debug prints are gone by now and the the only smp_processor_id()
invocation today is farther down in start_secondary() after locking
vector_lock which itself prevents reordering.
Even if the compiler would be allowed to reorder this, the code would still
be correct as GSBASE is set up early in the assembly code and is valid when
the CPU reaches start_secondary(), while the code at the time when this
barrier was added did the GSBASE setup in cpu_init().
As the barrier has zero value, remove it.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.875713771@linutronix.de
This was introduced with commit e1c467e690 ("x86, hotplug: Wake up CPU0
via NMI instead of INIT, SIPI, SIPI") to eventually support physical
hotplug of CPU0:
"We'll change this code in the future to wake up hard offlined CPU0 if
real platform and request are available."
11 years later this has not happened and physical hotplug is not officially
supported. Remove the cruft.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.768845190@linutronix.de
This was introduced together with commit e1c467e690 ("x86, hotplug: Wake
up CPU0 via NMI instead of INIT, SIPI, SIPI") to eventually support
physical hotplug of CPU0:
"We'll change this code in the future to wake up hard offlined CPU0 if
real platform and request are available."
11 years later this has not happened and physical hotplug is not officially
supported. Remove the cruft.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.715707999@linutronix.de
Pull compute express link fixes from Dan Williams:
- Fix a compilation issue with DEFINE_STATIC_SRCU() in the unit tests
- Fix leaking kernel memory to a root-only sysfs attribute
* tag 'cxl-fixes-6.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
cxl: Add missing return to cdat read error path
tools/testing/cxl: Use DEFINE_STATIC_SRCU()
Pull parisc architecture fixes from Helge Deller:
- Fix encoding of swp_entry due to added SWP_EXCLUSIVE flag
- Include reboot.h to avoid gcc-12 compiler warning
* tag 'parisc-for-6.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Fix encoding of swp_entry due to added SWP_EXCLUSIVE flag
parisc: kexec: include reboot.h
Pull ARM fixes from Russell King:
- fix unwinder for uleb128 case
- fix kernel-doc warnings for HP Jornada 7xx
- fix unbalanced stack on vfp success path
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 9297/1: vfp: avoid unbalanced stack on 'success' return path
ARM: 9296/1: HP Jornada 7XX: fix kernel-doc warnings
ARM: 9295/1: unwind:fix unwind abort for uleb128 case
Pull locking fix from Borislav Petkov:
- Make sure __down_read_common() is always inlined so that the callers'
names land in traceevents output and thus the blocked function can be
identified
* tag 'locking_urgent_for_v6.4_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwsem: Add __always_inline annotation to __down_read_common() and inlined callers
Pull perf fixes from Borislav Petkov:
- Make sure the PEBS buffer is flushed before reprogramming the
hardware so that the correct record sizes are used
- Update the sample size for AMD BRS events
- Fix a confusion with using the same on-stack struct with different
events in the event processing path
* tag 'perf_urgent_for_v6.4_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG
perf/x86: Fix missing sample size update on AMD BRS
perf/core: Fix perf_sample_data not properly initialized for different swevents in perf_tp_event()
Pull scheduler fix from Borislav Petkov:
- Fix a couple of kernel-doc warnings
* tag 'sched_urgent_for_v6.4_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: fix cid_lock kernel-doc warnings
Pull x86 fix from Borislav Petkov:
- Add the required PCI IDs so that the generic SMN accesses provided by
amd_nb.c work for drivers which switch to them. Add a PCI device ID
to k10temp's table so that latter is loaded on such systems too
* tag 'x86_urgent_for_v6.4_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hwmon: (k10temp) Add PCI ID for family 19, model 78h
x86/amd_nb: Add PCI ID for family 19h model 78h
Pull timer fix from Borislav Petkov:
- Prevent CPU state corruption when an active clockevent broadcast
device is replaced while the system is already in oneshot mode
* tag 'timers_urgent_for_v6.4_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick/broadcast: Make broadcast device replacement work correctly
Pull ext4 fixes from Ted Ts'o:
"Some ext4 bug fixes (mostly to address Syzbot reports)"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: bail out of ext4_xattr_ibody_get() fails for any reason
ext4: add bounds checking in get_max_inline_xattr_value_size()
ext4: add indication of ro vs r/w mounts in the mount message
ext4: fix deadlock when converting an inline directory in nojournal mode
ext4: improve error recovery code paths in __ext4_remount()
ext4: improve error handling from ext4_dirhash()
ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled
ext4: check iomap type only if ext4_iomap_begin() does not fail
ext4: avoid a potential slab-out-of-bounds in ext4_group_desc_csum
ext4: fix data races when using cached status extents
ext4: avoid deadlock in fs reclaim with page writeback
ext4: fix invalid free tracking in ext4_xattr_move_to_block()
ext4: remove a BUG_ON in ext4_mb_release_group_pa()
ext4: allow ext4_get_group_info() to fail
ext4: fix lockdep warning when enabling MMP
ext4: fix WARNING in mb_find_extent
Pull SCSI fix from James Bottomley:
"A single small fix for the UFS driver to fix a power management
failure"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: ufs: core: Fix I/O hang that occurs when BKOPS fails in W-LUN suspend
In ext4_update_inline_data(), if ext4_xattr_ibody_get() fails for any
reason, it's best if we just fail as opposed to stumbling on,
especially if the failure is EFSCORRUPTED.
Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Whether the file system is mounted read-only or read/write is more
important than the quota mode, which we are already printing. Add the
ro vs r/w indication since this can be helpful in debugging problems
from the console log.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
If there are failures while changing the mount options in
__ext4_remount(), we need to restore the old mount options.
This commit fixes two problem. The first is there is a chance that we
will free the old quota file names before a potential failure leading
to a use-after-free. The second problem addressed in this commit is
if there is a failed read/write to read-only transition, if the quota
has already been suspended, we need to renable quota handling.
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230506142419.984260-2-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When a file system currently mounted read/only is remounted
read/write, if we clear the SB_RDONLY flag too early, before the quota
is initialized, and there is another process/thread constantly
attempting to create a directory, it's possible to trigger the
WARN_ON_ONCE(dquot_initialize_needed(inode));
in ext4_xattr_block_set(), with the following stack trace:
WARNING: CPU: 0 PID: 5338 at fs/ext4/xattr.c:2141 ext4_xattr_block_set+0x2ef2/0x3680
RIP: 0010:ext4_xattr_block_set+0x2ef2/0x3680 fs/ext4/xattr.c:2141
Call Trace:
ext4_xattr_set_handle+0xcd4/0x15c0 fs/ext4/xattr.c:2458
ext4_initxattrs+0xa3/0x110 fs/ext4/xattr_security.c:44
security_inode_init_security+0x2df/0x3f0 security/security.c:1147
__ext4_new_inode+0x347e/0x43d0 fs/ext4/ialloc.c:1324
ext4_mkdir+0x425/0xce0 fs/ext4/namei.c:2992
vfs_mkdir+0x29d/0x450 fs/namei.c:4038
do_mkdirat+0x264/0x520 fs/namei.c:4061
__do_sys_mkdirat fs/namei.c:4076 [inline]
__se_sys_mkdirat fs/namei.c:4074 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4074
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230506142419.984260-1-tytso@mit.edu
Reported-by: syzbot+6385d7d3065524c5ca6d@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=6513f6cb5cd6b5fc9f37e3bb70d273b94be9c34c
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:
CPU0 CPU1
ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever
Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock.
Reported-by: syzbot+6898da502aef574c5f8a@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/0000000000004c66b405fa108e27@google.com
Fixes: c8585c6fca ("ext4: fix races between changing inode journal mode and ext4_writepages")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230504124723.20205-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Previously, ext4_get_group_info() would treat an invalid group number
as BUG(), since in theory it should never happen. However, if a
malicious attaker (or fuzzer) modifies the superblock via the block
device while it is the file system is mounted, it is possible for
s_first_data_block to get set to a very large number. In that case,
when calculating the block group of some block number (such as the
starting block of a preallocation region), could result in an
underflow and very large block group number. Then the BUG_ON check in
ext4_get_group_info() would fire, resutling in a denial of service
attack that can be triggered by root or someone with write access to
the block device.
For a quality of implementation perspective, it's best that even if
the system administrator does something that they shouldn't, that it
will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info()
will call ext4_error and return NULL. We also add fallback code in
all of the callers of ext4_get_group_info() that it might NULL.
Also, since ext4_get_group_info() was already borderline to be an
inline function, un-inline it. The results in a next reduction of the
compiled text size of ext4 by roughly 2k.
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230430154311.579720-2-tytso@mit.edu
Reported-by: syzbot+e2efa3efc15a1c9e95c3@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=69b28112e098b070f639efb356393af3ffec4220
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Pull block fixes from Jens Axboe:
"Just a few minor fixes for drivers, and a deletion of a file that is
woefully out-of-date these days"
* tag 'block-6.4-2023-05-13' of git://git.kernel.dk/linux:
Documentation/block: drop the request.rst file
ublk: fix command op code check
block/rnbd: replace REQ_OP_FLUSH with REQ_OP_WRITE
nbd: Fix debugfs_create_dir error checking
SYM_FUNC_START_LOCAL_NOALIGN() adds an endbr leading to this layout
(leaving only the last 2 bytes of the address):
3bff <zen_untrain_ret>:
3bff: f3 0f 1e fa endbr64
3c03: f6 test $0xcc,%bl
3c04 <__x86_return_thunk>:
3c04: c3 ret
3c05: cc int3
3c06: 0f ae e8 lfence
However, "the RET at __x86_return_thunk must be on a 64 byte boundary,
for alignment within the BTB."
Use SYM_START instead.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull more btrfs fixes from David Sterba:
- fix incorrect number of bitmap entries for space cache if loading is
interrupted by some error
- fix backref walking, this breaks a mode of LOGICAL_INO_V2 ioctl that
is used in deduplication tools
- zoned mode fixes:
- properly finish zone reserved for relocation
- correctly calculate super block zone end on ZNS
- properly initialize new extent buffer for redirty
- make mount option clear_cache work with block-group-tree, to rebuild
free-space-tree instead of temporarily disabling it that would lead
to a forced read-only mount
- fix alignment check for offset when printing extent item
* tag 'for-6.4-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: make clear_cache mount option to rebuild FST without disabling it
btrfs: zero the buffer before marking it dirty in btrfs_redirty_list_add
btrfs: zoned: fix full zone super block reading on ZNS
btrfs: zoned: zone finish data relocation BG with last IO
btrfs: fix backref walking not returning all inode refs
btrfs: fix space cache inconsistency after error loading it from disk
btrfs: print-tree: parent bytenr must be aligned to sector size
Pull cifs client fixes from Steve French:
- fix for copy_file_range bug for very large files that are multiples
of rsize
- do not ignore "isolated transport" flag if set on share
- set rasize default better
- three fixes related to shutdown and freezing (fixes 4 xfstests, and
closes deferred handles faster in some places that were missed)
* tag '6.4-rc1-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: release leases for deferred close handles when freezing
smb3: fix problem remounting a share after shutdown
SMB3: force unmount was failing to close deferred close files
smb3: improve parallel reads of large files
do not reuse connection if share marked as isolated
cifs: fix pcchunk length type in smb2_copychunk_range
