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Filename Latest commit message Latest commit date
Zhang Jianhua 278e483dc7 efi: Change down_interruptible() in virt_efi_reset_system() to down_trylock()
commit 38fa3206bf441911258e5001ac8b6738693f8d82 upstream.

While reboot the system by sysrq, the following bug will be occur.

BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:90
in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 10052, name: rc.shutdown
CPU: 3 PID: 10052 Comm: rc.shutdown Tainted: G        W O      5.10.0 #1
Call trace:
 dump_backtrace+0x0/0x1c8
 show_stack+0x18/0x28
 dump_stack+0xd0/0x110
 ___might_sleep+0x14c/0x160
 __might_sleep+0x74/0x88
 down_interruptible+0x40/0x118
 virt_efi_reset_system+0x3c/0xd0
 efi_reboot+0xd4/0x11c
 machine_restart+0x60/0x9c
 emergency_restart+0x1c/0x2c
 sysrq_handle_reboot+0x1c/0x2c
 __handle_sysrq+0xd0/0x194
 write_sysrq_trigger+0xbc/0xe4
 proc_reg_write+0xd4/0xf0
 vfs_write+0xa8/0x148
 ksys_write+0x6c/0xd8
 __arm64_sys_write+0x18/0x28
 el0_svc_common.constprop.3+0xe4/0x16c
 do_el0_svc+0x1c/0x2c
 el0_svc+0x20/0x30
 el0_sync_handler+0x80/0x17c
 el0_sync+0x158/0x180

The reason for this problem is that irq has been disabled in
machine_restart() and then it calls down_interruptible() in
virt_efi_reset_system(), which would occur sleep in irq context,
it is dangerous! Commit 99409b935c9a("locking/semaphore: Add
might_sleep() to down_*() family") add might_sleep() in
down_interruptible(), so the bug info is here. down_trylock()
can solve this problem, cause there is no might_sleep.

--------

Cc: <stable@vger.kernel.org>
Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-20 11:40:14 +02:00
arch x86/resctrl: Free the ctrlval arrays when domain_setup_mon_state() fails 2021-10-20 11:40:13 +02:00
block Revert "block, bfq: honor already-setup queue merges" 2021-10-06 15:42:34 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation 2021-09-22 12:26:43 +02:00
drivers efi: Change down_interruptible() in virt_efi_reset_system() to down_trylock() 2021-10-20 11:40:14 +02:00
fs btrfs: check for error when looking up inode during dir entry replay 2021-10-20 11:40:13 +02:00
include sched: Always inline is_percpu_thread() 2021-10-17 10:42:34 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel bpf: Fix integer overflow in prealloc_elems_and_freelist() 2021-10-13 10:08:18 +02:00
lib Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH 2021-09-26 14:07:10 +02:00
LICENSES
mm mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range() 2021-09-22 12:26:43 +02:00
net mac80211: check return value of rhashtable_init 2021-10-17 10:42:34 +02:00
samples samples: bpf: Fix tracex7 error raised on the missing argument 2021-09-22 12:26:30 +02:00
scripts nds32/ftrace: Fix Error: invalid operands (*UND* and *UND* sections) for `^' 2021-10-20 11:40:12 +02:00
security apparmor: remove duplicate macro list_entry_is_head() 2021-09-26 14:07:06 +02:00
sound ALSA: hda/realtek: Fix the mic type detection issue for ASUS G551JW 2021-10-20 11:40:12 +02:00
tools tools/vm/page-types: remove dependency on opt_file for idle page tracking 2021-10-09 14:39:50 +02:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.154 2021-10-17 10:42:35 +02:00
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.