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Filename Latest commit message Latest commit date
Darrick J. Wong b8233f7b2f xfs: periodically yield scrub threads to the scheduler
[ Upstream commit 5d1116d4c6af3e580f1ed0382ca5a94bd65a34cf ]

Christoph Hellwig complained about the following soft lockup warning
when running scrub after generic/175 when preemption is disabled and
slub debugging is enabled:

watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [xfs_scrub:161]
Modules linked in:
irq event stamp: 41692326
hardirqs last  enabled at (41692325): [<ffffffff8232c3b7>] _raw_0
hardirqs last disabled at (41692326): [<ffffffff81001c5a>] trace0
softirqs last  enabled at (41684994): [<ffffffff8260031f>] __do_e
softirqs last disabled at (41684987): [<ffffffff81127d8c>] irq_e0
CPU: 3 PID: 16189 Comm: xfs_scrub Not tainted 5.4.0-rc3+ #30
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.124
RIP: 0010:_raw_spin_unlock_irqrestore+0x39/0x40
Code: 89 f3 be 01 00 00 00 e8 d5 3a e5 fe 48 89 ef e8 ed 87 e5 f2
RSP: 0018:ffffc9000233f970 EFLAGS: 00000286 ORIG_RAX: ffffffffff3
RAX: ffff88813b398040 RBX: 0000000000000286 RCX: 0000000000000006
RDX: 0000000000000006 RSI: ffff88813b3988c0 RDI: ffff88813b398040
RBP: ffff888137958640 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00042b0c00
R13: 0000000000000001 R14: ffff88810ac32308 R15: ffff8881376fc040
FS:  00007f6113dea700(0000) GS:ffff88813bb80000(0000) knlGS:00000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6113de8ff8 CR3: 000000012f290000 CR4: 00000000000006e0
Call Trace:
 free_debug_processing+0x1dd/0x240
 __slab_free+0x231/0x410
 kmem_cache_free+0x30e/0x360
 xchk_ag_btcur_free+0x76/0xb0
 xchk_ag_free+0x10/0x80
 xchk_bmap_iextent_xref.isra.14+0xd9/0x120
 xchk_bmap_iextent+0x187/0x210
 xchk_bmap+0x2e0/0x3b0
 xfs_scrub_metadata+0x2e7/0x500
 xfs_ioc_scrub_metadata+0x4a/0xa0
 xfs_file_ioctl+0x58a/0xcd0
 do_vfs_ioctl+0xa0/0x6f0
 ksys_ioctl+0x5b/0x90
 __x64_sys_ioctl+0x11/0x20
 do_syscall_64+0x4b/0x1a0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

If preemption is disabled, all metadata buffers needed to perform the
scrub are already in memory, and there are a lot of records to check,
it's possible that the scrub thread will run for an extended period of
time without sleeping for IO or any other reason.  Then the watchdog
timer or the RCU stall timeout can trigger, producing the backtrace
above.

To fix this problem, call cond_resched() from the scrub thread so that
we back out to the scheduler whenever necessary.

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-09 10:20:06 +01:00
arch arm64: dts: meson: odroid-c2: Disable usb_otg bus to avoid power failed warning 2020-01-09 10:20:05 +01:00
block compat_ioctl: block: handle BLKGETZONESZ/BLKGETNRZONES 2020-01-09 10:19:58 +01:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto KEYS: asymmetric: return ENOMEM if akcipher_request_alloc() fails 2019-12-31 16:46:07 +01:00
Documentation dt-bindings: clock: renesas: rcar-usb2-clock-sel: Fix typo in example 2020-01-09 10:20:05 +01:00
drivers drm/i915/execlists: Fix annotation for decoupling virtual request 2020-01-09 10:20:06 +01:00
fs xfs: periodically yield scrub threads to the scheduler 2020-01-09 10:20:06 +01:00
include regulator: ab8500: Remove AB8505 USB regulator 2020-01-09 10:20:04 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel kernel/module.c: wakeup processes in module_wq on module unload 2020-01-09 10:20:02 +01:00
lib ubsan, x86: Annotate and allow __ubsan_handle_shift_out_of_bounds() in uaccess regions 2019-12-31 16:44:25 +01:00
LICENSES
mm arm64: Revert support for execute-only user mappings 2020-01-09 10:20:01 +01:00
net Bluetooth: Fix memory leak in hci_connect_le_scan 2020-01-09 10:20:04 +01:00
samples samples/trace_printk: Wait for IRQ work to finish 2020-01-09 10:20:00 +01:00
scripts gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS again 2020-01-09 10:19:57 +01:00
security apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock 2020-01-09 10:20:00 +01:00
sound ALSA: firewire-motu: Correct a typo in the clock proc string 2020-01-09 10:20:01 +01:00
tools perf callchain: Fix segfault in thread__resolve_callchain_sample() 2020-01-09 10:20:02 +01:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-09 10:20:00 +01:00
virt KVM: arm/arm64: Properly handle faulting of device mappings 2019-12-31 16:46:24 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4.8 2020-01-04 19:19:19 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.