No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Anton Eidelman 763303a83a nvme-multipath: fix crash in nvme_mpath_clear_ctrl_paths
nvme_mpath_clear_ctrl_paths() iterates through
the ctrl->namespaces list while holding ctrl->scan_lock.
This does not seem to be the correct way of protecting
from concurrent list modification.

Specifically, nvme_scan_work() sorts ctrl->namespaces
AFTER unlocking scan_lock.

This may result in the following (rare) crash in ctrl disconnect
during scan_work:

    BUG: kernel NULL pointer dereference, address: 0000000000000050
    Oops: 0000 [#1] SMP PTI
    CPU: 0 PID: 3995 Comm: nvme 5.3.5-050305-generic
    RIP: 0010:nvme_mpath_clear_current_path+0xe/0x90 [nvme_core]
    ...
    Call Trace:
     nvme_mpath_clear_ctrl_paths+0x3c/0x70 [nvme_core]
     nvme_remove_namespaces+0x35/0xe0 [nvme_core]
     nvme_do_delete_ctrl+0x47/0x90 [nvme_core]
     nvme_sysfs_delete+0x49/0x60 [nvme_core]
     dev_attr_store+0x17/0x30
     sysfs_kf_write+0x3e/0x50
     kernfs_fop_write+0x11e/0x1a0
     __vfs_write+0x1b/0x40
     vfs_write+0xb9/0x1a0
     ksys_write+0x67/0xe0
     __x64_sys_write+0x1a/0x20
     do_syscall_64+0x5a/0x130
     entry_SYSCALL_64_after_hwframe+0x44/0xa9
    RIP: 0033:0x7f8d02bfb154

Fix:
After taking scan_lock in nvme_mpath_clear_ctrl_paths()
down_read(&ctrl->namespaces_rwsem) as well to make list traversal safe.
This will not cause deadlocks because taking scan_lock never happens
while holding the namespaces_rwsem.
Moreover, scan work downs namespaces_rwsem in the same order.

Alternative: sort ctrl->namespaces in nvme_scan_work()
while still holding the scan_lock.
This would leave nvme_mpath_clear_ctrl_paths() without correct protection
against ctrl->namespaces modification by anyone other than scan_work.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2019-11-06 00:30:37 +09:00
arch um-ubd: Entrust re-queue to the upper layers 2019-10-29 10:07:41 -06:00
block iocost: don't nest spin_lock_irq in ioc_weight_write() 2019-10-31 11:40:57 -06:00
certs
crypto 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
Documentation ARM: SoC fixes 2019-10-25 16:00:47 -04:00
drivers nvme-multipath: fix crash in nvme_mpath_clear_ctrl_paths 2019-11-06 00:30:37 +09:00
fs io_uring: ensure we clear io_kiocb->result before each issue 2019-10-30 14:45:22 -06:00
include Driver core fix for 5.4-rc5 2019-10-26 15:23:08 -04:00
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 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-10-27 07:04:22 -04:00
lib lib/vdso: Make clock_getres() POSIX compliant again 2019-10-23 14:48:23 +02:00
LICENSES
mm mm/thp: allow dropping THP from page cache 2019-10-19 06:32:33 -04:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-19 17:09:11 -04:00
samples samples/bpf: Add a workaround for asm_inline 2019-10-03 17:37:11 +02:00
scripts Modules fixes for v5.4-rc5 2019-10-25 16:11:55 -04:00
security selinux/stable-5.4 PR 20191007 2019-10-08 10:51:37 -07:00
sound ALSA: hda: Add Tigerlake/Jasperlake PCI ID 2019-10-23 06:28:50 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-10-27 06:59:34 -04:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM/arm fixes for 5.4, take #2 2019-10-22 13:31:29 +02:00
.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 A few MIPS fixes: 2019-10-26 19:43:12 -04:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS A few MIPS fixes: 2019-10-26 19:43:12 -04:00
Makefile Linux 5.4-rc5 2019-10-27 13:19:19 -04:00
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.