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Waiman Long 3cb5953071 sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed
[ Upstream commit b6e8d40d43 ]

With cgroup v2, the cpuset's cpus_allowed mask can be empty indicating
that the cpuset will just use the effective CPUs of its parent. So
cpuset_can_attach() can call task_can_attach() with an empty mask.
This can lead to cpumask_any_and() returns nr_cpu_ids causing the call
to dl_bw_of() to crash due to percpu value access of an out of bound
CPU value. For example:

	[80468.182258] BUG: unable to handle page fault for address: ffffffff8b6648b0
	  :
	[80468.191019] RIP: 0010:dl_cpu_busy+0x30/0x2b0
	  :
	[80468.207946] Call Trace:
	[80468.208947]  cpuset_can_attach+0xa0/0x140
	[80468.209953]  cgroup_migrate_execute+0x8c/0x490
	[80468.210931]  cgroup_update_dfl_csses+0x254/0x270
	[80468.211898]  cgroup_subtree_control_write+0x322/0x400
	[80468.212854]  kernfs_fop_write_iter+0x11c/0x1b0
	[80468.213777]  new_sync_write+0x11f/0x1b0
	[80468.214689]  vfs_write+0x1eb/0x280
	[80468.215592]  ksys_write+0x5f/0xe0
	[80468.216463]  do_syscall_64+0x5c/0x80
	[80468.224287]  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fix that by using effective_cpus instead. For cgroup v1, effective_cpus
is the same as cpus_allowed. For v2, effective_cpus is the real cpumask
to be used by tasks within the cpuset anyway.

Also update task_can_attach()'s 2nd argument name to cs_effective_cpus to
reflect the change. In addition, a check is added to task_can_attach()
to guard against the possibility that cpumask_any_and() may return a
value >= nr_cpu_ids.

Fixes: 7f51412a41 ("sched/deadline: Fix bandwidth check/update when migrating tasks between exclusive cpusets")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20220803015451.2219567-1-longman@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-19 17:52:48 +08:00
arch powerpc/pci: Fix PHB numbering when using opal-phbid 2023-04-19 17:52:48 +08:00
block block: ensure iov_iter advances for added pages 2023-04-19 17:52:40 +08:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2023-04-19 17:50:34 +08:00
crypto crypto: memneq - move into lib/ 2023-04-19 17:50:35 +08:00
Documentation media: hevc: Embedded indexes in RPS 2023-04-19 17:52:24 +08:00
drivers tty: serial: fsl_lpuart: correct the count of break characters 2023-04-19 17:52:46 +08:00
fs f2fs: fix to remove F2FS_COMPR_FL and tag F2FS_NOCOMP_FL at the same time 2023-04-19 17:52:47 +08:00
include sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed 2023-04-19 17:52:48 +08:00
init stack: Declare {randomize_,}kstack_offset to fix Sparse warnings 2023-04-19 17:52:12 +08:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2023-04-19 17:49:52 +08:00
kernel sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed 2023-04-19 17:52:48 +08:00
lib lib/smp_processor_id: fix imbalanced instrumentation_end() call 2023-04-19 17:52:44 +08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/mmap.c: fix missing call to vm_unacct_memory in mmap_region 2023-04-19 17:52:39 +08:00
net net: 9p: fix refcount leak in p9_read_work() error handling 2023-04-19 17:52:44 +08:00
samples samples/landlock: Format with clang-format 2023-04-19 17:50:01 +08:00
scripts scripts/faddr2line: Fix vmlinux detection on arm64 2023-04-19 17:52:48 +08:00
security selinux: Add boundary check in put_entry() 2023-04-19 17:52:09 +08:00
sound ASoC: mchp-spdifrx: disable end of block interrupt on failures 2023-04-19 17:52:46 +08:00
tools genelf: Use HAVE_LIBCRYPTO_SUPPORT, not the never defined HAVE_LIBCRYPTO 2023-04-19 17:52:48 +08:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2023-04-19 17:44:58 +08:00
virt KVM: Don't set Accessed/Dirty bits for ZERO_PAGE 2023-04-19 17:52:31 +08:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Input: goodix - add a goodix.h header file 2023-04-19 17:50:59 +08:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2023-04-19 17:51:58 +08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.