Go to file
Linus Torvalds 66e4b63624 Two fixes for the timer wheel:
- A timer which is already expired at enqueue time can set the
    base->next_expiry value backwards. As a consequence base->clk can be set
    back as well. This can lead to timers expiring early. Add a sanity check
    to prevent this.
 
  - When a timer is queued with an expiry time beyond the wheel capacity
    then it should be queued in the bucket of the last wheel level which is
    expiring last. The code adjusts expiry time to the maximum wheel
    capacity, which is only correct when the wheel clock is 0. Aside of that
    the check whether the delta is larger than wheel capacity does not check
    the delta, it checks the expiry value itself. As a result timers can
    expire at random.
 
    Fix this by checking the right variable and adjust expiry time so it
    becomes base->clock plus capacity which places it into the outmost
    bucket in the last wheel level.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAl8URRQTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoQVMD/0VMkT36A8SKbPudMLZ5REp63E629wQ
 yuGJz9IJPE1NYB25PXL0TmVAQpseXKDKh3eSP2ac6Ao1FTUk/He/CwF2tsGvu+tm
 kxpuPQgeUF8BeF7WzE21k4NeAmTv8eaIxirQPRQBRJldHuNG9u0l1u8dr0rT2mQG
 N0djinQvM4bRUVa10l4dz6gE2F0Egjv5sIZohv3E6ORwisJxJoZUUFMlqfuS+2Xt
 lOebR8juJahIDRM3ihhZfXJI2tCPD/FnrcMWbk1z3NbsE6C2MiG4ncrjxR2MY81Q
 zRr3CrN6TgjTUkvSMOP1SuFePEKLc/2rl5dg9EcGEFNOyggPEezSB/sL1HavRsV9
 2s/hmLB6VR5GQwhMnhbLTq3jAI9M9P1S4VEoKHlDs8LoCxtQ+g+2IKmSVqKWXFuO
 6AscBbNQkEbrkTx+OkbHWYc7+RLQE87ryCNODeETzSwE0H3NLk/GRQirq6LO9ESq
 AjVg5085YZXEIzistsSON0aTdY0eIIVsmaYmFOI0qNPnSUCOPlHIXwD+ju1WEW4h
 QtM6BW6xggydgSLgOWQQzKpgBfLW3j7F4r7cFsNCjaQ7UtDQMPMMm+ATBpoT8vdA
 EHR/FC4U8ABiXpnleh87B1WCpQr6p6qo95eIbe5UxY3yPdPb32s1/+ycFngW9XPj
 B4353TQp7aNRUw==
 =aCiv
 -----END PGP SIGNATURE-----

Merge tag 'timers-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull timer fixes from Thomas Gleixner:
 "Two fixes for the timer wheel:

   - A timer which is already expired at enqueue time can set the
     base->next_expiry value backwards. As a consequence base->clk can
     be set back as well. This can lead to timers expiring early. Add a
     sanity check to prevent this.

   - When a timer is queued with an expiry time beyond the wheel
     capacity then it should be queued in the bucket of the last wheel
     level which is expiring last.

     The code adjusted the expiry time to the maximum wheel capacity,
     which is only correct when the wheel clock is 0. Aside of that the
     check whether the delta is larger than wheel capacity does not
     check the delta, it checks the expiry value itself. As a result
     timers can expire at random.

     Fix this by checking the right variable and adjust expiry time so
     it becomes base->clock plus capacity which places it into the
     outmost bucket in the last wheel level"

* tag 'timers-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timer: Fix wheel index calculation on last level
  timer: Prevent base->clk from moving backward
2020-07-19 12:06:08 -07:00
arch Two fixes for the interrupt subsystem: 2020-07-19 11:53:08 -07:00
block block-5.8-2020-07-10 2020-07-10 09:55:46 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-15 15:49:04 -07:00
Documentation powerpc fixes for 5.8 #7 2020-07-18 10:45:17 -07:00
drivers Two fixes for the interrupt subsystem: 2020-07-19 11:53:08 -07:00
fs More NFS Client Bugfixes for Linux 5.8 2020-07-17 16:37:52 -07:00
include A set of scheduler fixes: 2020-07-19 11:55:24 -07:00
init kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang 2020-07-02 00:57:45 +09:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Two fixes for the timer wheel: 2020-07-19 12:06:08 -07:00
lib RISC-V Fixes for 5.8-rc5 (ideally) 2020-07-11 19:22:46 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: document warning in move_normal_pmd() and make it warn only once 2020-07-13 11:37:39 -07:00
net xprtrdma: fix incorrect header size calculations 2020-07-15 13:01:01 -04:00
samples samples/vfs: avoid warning in statx override 2020-07-03 16:15:25 -07:00
scripts kbuild: Move -Wtype-limits to W=2 2020-07-09 18:00:56 -07:00
security integrity/ima: switch to using __kernel_read 2020-07-08 08:27:57 +02:00
sound sound fixes for 5.8-rc6 2020-07-17 08:48:19 -07:00
tools powerpc fixes for 5.8 #7 2020-07-18 10:45:17 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt kvm: use more precise cast and do not drop __user 2020-07-02 05:39:31 -04:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +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: Do not track defconfig from make savedefconfig 2020-07-05 16:15:46 +09:00
.mailmap MAINTAINERS: update email address for Gerald Schaefer 2020-07-10 15:06:49 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
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 regulator: Fixes for v5.8 2020-07-17 10:20:26 -07:00
Makefile Linux 5.8-rc5 2020-07-12 16:34:50 -07:00
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.