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.
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Pull networking fixes from David Miller:
"One last pull request before heading to Vancouver for LPC, here we have:
1) Don't forget to free VSI contexts during ice driver unload, from
Victor Raj.
2) Don't forget napi delete calls during device remove in ice driver,
from Dave Ertman.
3) Don't request VLAN tag insertion of ibmvnic device when SKB
doesn't have VLAN tags at all.
4) IPV4 frag handling code has to accomodate the situation where two
threads try to insert the same fragment into the hash table at the
same time. From Eric Dumazet.
5) Relatedly, don't flow separate on protocol ports for fragmented
frames, also from Eric Dumazet.
6) Memory leaks in qed driver, from Denis Bolotin.
7) Correct valid MTU range in smsc95xx driver, from Stefan Wahren.
8) Validate cls_flower nested policies properly, from Jakub Kicinski.
9) Clearing of stats counters in mc88e6xxx driver doesn't retain
important bits in the G1_STATS_OP register causing the chip to
hang. Fix from Andrew Lunn"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (41 commits)
act_mirred: clear skb->tstamp on redirect
net: dsa: mv88e6xxx: Fix clearing of stats counters
tipc: fix link re-establish failure
net: sched: cls_flower: validate nested enc_opts_policy to avoid warning
net: mvneta: correct typo
flow_dissector: do not dissect l4 ports for fragments
net: qualcomm: rmnet: Fix incorrect assignment of real_dev
net: aquantia: allow rx checksum offload configuration
net: aquantia: invalid checksumm offload implementation
net: aquantia: fixed enable unicast on 32 macvlan
net: aquantia: fix potential IOMMU fault after driver unbind
net: aquantia: synchronized flow control between mac/phy
net: smsc95xx: Fix MTU range
net: stmmac: Fix RX packet size > 8191
qed: Fix potential memory corruption
qed: Fix SPQ entries not returned to pool in error flows
qed: Fix blocking/unlimited SPQ entries leak
qed: Fix memory/entry leak in qed_init_sp_request()
inet: frags: better deal with smp races
net: hns3: bugfix for not checking return value
...
Pull Kbuild fixes from Masahiro Yamada:
- fix build errors in binrpm-pkg and bindeb-pkg targets
- fix false positive matches in merge_config.sh
- fix build version mismatch in deb-pkg target
- fix dtbs_install handling in (bin)deb-pkg target
- revert a commit that allows setlocalversion to write to source tree
* tag 'kbuild-fixes-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
builddeb: Fix inclusion of dtbs in debian package
Revert "scripts/setlocalversion: git: Make -dirty check more robust"
kbuild: deb-pkg: fix too low build version number
kconfig: merge_config: avoid false positive matches from comment lines
kbuild: deb-pkg: fix bindeb-pkg breakage when O= is used
kbuild: rpm-pkg: fix binrpm-pkg breakage when O= is used
If sch_fq is used at ingress, skbs that might have been
timestamped by net_timestamp_set() if a packet capture
is requesting timestamps could be delayed by arbitrary
amount of time, since sch_fq time base is MONOTONIC.
Fix this problem by moving code from sch_netem.c to act_mirred.c.
Fixes: fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull btrfs fixes from David Sterba:
"Several fixes to recent release (4.19, fixes tagged for stable) and
other fixes"
* tag 'for-4.20-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Btrfs: fix missing delayed iputs on unmount
Btrfs: fix data corruption due to cloning of eof block
Btrfs: fix infinite loop on inode eviction after deduplication of eof block
Btrfs: fix deadlock on tree root leaf when finding free extent
btrfs: avoid link error with CONFIG_NO_AUTO_INLINE
btrfs: tree-checker: Fix misleading group system information
Btrfs: fix missing data checksums after a ranged fsync (msync)
btrfs: fix pinned underflow after transaction aborted
Btrfs: fix cur_offset in the error case for nocow
Commit 37c8a5fafa3b ("kbuild: consolidate Devicetree dtb build rules")
moved the location of 'dtbs_install' target which caused dtbs to not be
installed when building debian package with 'bindeb-pkg' target. Update
the builddeb script to use the same logic that determines if there's a
'dtbs_install' target which is presence of the arch dts directory. Also,
use CONFIG_OF_EARLY_FLATTREE instead of CONFIG_OF as that's a better
indication of whether we are building dtbs.
This commit will also have the side effect of installing dtbs on any
arch that has dts files. Previously, it was dependent on whether the
arch defined 'dtbs_install'.
Fixes: 37c8a5fafa3b ("kbuild: consolidate Devicetree dtb build rules")
Reported-by: Nuno Gonçalves <nunojpg@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The mv88e6161 would sometime fail to probe with a timeout waiting for
the switch to complete an operation. This operation is supposed to
clear the statistics counters. However, due to a read/modify/write,
without the needed mask, the operation actually carried out was more
random, with invalid parameters, resulting in the switch not
responding. We need to preserve the histogram mode bits, so apply a
mask to keep them.
Reported-by: Chris Healy <Chris.Healy@zii.aero>
Fixes: 40cff8fca9e3 ("net: dsa: mv88e6xxx: Fix stats histogram mode")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull ext4 fixes from Ted Ts'o:
"A large number of ext4 bug fixes, mostly buffer and memory leaks on
error return cleanup paths"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: missing !bh check in ext4_xattr_inode_write()
ext4: fix buffer leak in __ext4_read_dirblock() on error path
ext4: fix buffer leak in ext4_expand_extra_isize_ea() on error path
ext4: fix buffer leak in ext4_xattr_move_to_block() on error path
ext4: release bs.bh before re-using in ext4_xattr_block_find()
ext4: fix buffer leak in ext4_xattr_get_block() on error path
ext4: fix possible leak of s_journal_flag_rwsem in error path
ext4: fix possible leak of sbi->s_group_desc_leak in error path
ext4: remove unneeded brelse call in ext4_xattr_inode_update_ref()
ext4: avoid possible double brelse() in add_new_gdb() on error path
ext4: avoid buffer leak in ext4_orphan_add() after prior errors
ext4: avoid buffer leak on shutdown in ext4_mark_iloc_dirty()
ext4: fix possible inode leak in the retry loop of ext4_resize_fs()
ext4: fix missing cleanup if ext4_alloc_flex_bg_array() fails while resizing
ext4: add missing brelse() update_backups()'s error path
ext4: add missing brelse() add_new_gdb_meta_bg()'s error path
ext4: add missing brelse() in set_flexbg_block_bitmap()'s error path
ext4: avoid potential extra brelse in setup_new_flex_group_blocks()
There's a race between close_ctree() and cleaner_kthread().
close_ctree() sets btrfs_fs_closing(), and the cleaner stops when it
sees it set, but this is racy; the cleaner might have already checked
the bit and could be cleaning stuff. In particular, if it deletes unused
block groups, it will create delayed iputs for the free space cache
inodes. As of "btrfs: don't run delayed_iputs in commit", we're no
longer running delayed iputs after a commit. Therefore, if the cleaner
creates more delayed iputs after delayed iputs are run in
btrfs_commit_super(), we will leak inodes on unmount and get a busy
inode crash from the VFS.
Fix it by parking the cleaner before we actually close anything. Then,
any remaining delayed iputs will always be handled in
btrfs_commit_super(). This also ensures that the commit in close_ctree()
is really the last commit, so we can get rid of the commit in
cleaner_kthread().
The fstest/generic/475 followed by 476 can trigger a crash that
manifests as a slab corruption caused by accessing the freed kthread
structure by a wake up function. Sample trace:
[ 5657.077612] BUG: unable to handle kernel NULL pointer dereference at 00000000000000cc
[ 5657.079432] PGD 1c57a067 P4D 1c57a067 PUD da10067 PMD 0
[ 5657.080661] Oops: 0000 [#1] PREEMPT SMP
[ 5657.081592] CPU: 1 PID: 5157 Comm: fsstress Tainted: G W 4.19.0-rc8-default+ #323
[ 5657.083703] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626cc-prebuilt.qemu-project.org 04/01/2014
[ 5657.086577] RIP: 0010:shrink_page_list+0x2f9/0xe90
[ 5657.091937] RSP: 0018:ffffb5c745c8f728 EFLAGS: 00010287
[ 5657.092953] RAX: 0000000000000074 RBX: ffffb5c745c8f830 RCX: 0000000000000000
[ 5657.094590] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9a8747fdf3d0
[ 5657.095987] RBP: ffffb5c745c8f9e0 R08: 0000000000000000 R09: 0000000000000000
[ 5657.097159] R10: ffff9a8747fdf5e8 R11: 0000000000000000 R12: ffffb5c745c8f788
[ 5657.098513] R13: ffff9a877f6ff2c0 R14: ffff9a877f6ff2c8 R15: dead000000000200
[ 5657.099689] FS: 00007f948d853b80(0000) GS:ffff9a877d600000(0000) knlGS:0000000000000000
[ 5657.101032] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5657.101953] CR2: 00000000000000cc CR3: 00000000684bd000 CR4: 00000000000006e0
[ 5657.103159] Call Trace:
[ 5657.103776] shrink_inactive_list+0x194/0x410
[ 5657.104671] shrink_node_memcg.constprop.84+0x39a/0x6a0
[ 5657.105750] shrink_node+0x62/0x1c0
[ 5657.106529] try_to_free_pages+0x1a4/0x500
[ 5657.107408] __alloc_pages_slowpath+0x2c9/0xb20
[ 5657.108418] __alloc_pages_nodemask+0x268/0x2b0
[ 5657.109348] kmalloc_large_node+0x37/0x90
[ 5657.110205] __kmalloc_node+0x236/0x310
[ 5657.111014] kvmalloc_node+0x3e/0x70
Fixes: 30928e9baac2 ("btrfs: don't run delayed_iputs in commit")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add trace ]
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit 6147b1cf19651c7de297e69108b141fb30aa2349.
The reverted patch results in attempted write access to the source
repository, even if that repository is mounted read-only.
Output from "strace git status -uno --porcelain":
getcwd("/tmp/linux-test", 129) = 16
open("/tmp/linux-test/.git/index.lock", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0666) =
-1 EROFS (Read-only file system)
While git appears to be able to handle this situation, a monitored
build environment (such as the one used for Chrome OS kernel builds)
may detect it and bail out with an access violation error. On top of
that, the attempted write access suggests that git _will_ write to the
file even if a build output directory is specified. Users may have the
reasonable expectation that the source repository remains untouched in
that situation.
Fixes: 6147b1cf19651 ("scripts/setlocalversion: git: Make -dirty check more robust"
Cc: Genki Sky <sky@genki.is>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
When a link failure is detected locally, the link is reset, the flag
link->in_session is set to false, and a RESET_MSG with the 'stopping'
bit set is sent to the peer.
The purpose of this bit is to inform the peer that this endpoint just
is going down, and that the peer should handle the reception of this
particular RESET message as a local failure. This forces the peer to
accept another RESET or ACTIVATE message from this endpoint before it
can re-establish the link. This again is necessary to ensure that
link session numbers are properly exchanged before the link comes up
again.
If a failure is detected locally at the same time at the peer endpoint
this will do the same, which is also a correct behavior.
However, when receiving such messages, the endpoints will not
distinguish between 'stopping' RESETs and ordinary ones when it comes
to updating session numbers. Both endpoints will copy the received
session number and set their 'in_session' flags to true at the
reception, while they are still expecting another RESET from the
peer before they can go ahead and re-establish. This is contradictory,
since, after applying the validation check referred to below, the
'in_session' flag will cause rejection of all such messages, and the
link will never come up again.
We now fix this by not only handling received RESET/STOPPING messages
as a local failure, but also by omitting to set a new session number
and the 'in_session' flag in such cases.
Fixes: 7ea817f4e832 ("tipc: check session number before accepting link protocol messages")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull x86 fixes from Thomas Gleixner:
"A set of x86 fixes:
- Cure the LDT remapping to user space on 5 level paging which ended
up in the KASLR space
- Remove LDT mapping before freeing the LDT pages
- Make NFIT MCE handling more robust
- Unbreak the VSMP build by removing the dependency on paravirt ops
- Support broken PIT emulation on Microsoft hyperV
- Don't trace vmware_sched_clock() to avoid tracer recursion
- Remove -pipe from KBUILD CFLAGS which breaks clang and is also
slower on GCC
- Trivial coding style and typo fixes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu/vmware: Do not trace vmware_sched_clock()
x86/vsmp: Remove dependency on pv_irq_ops
x86/ldt: Remove unused variable in map_ldt_struct()
x86/ldt: Unmap PTEs for the slot before freeing LDT pages
x86/mm: Move LDT remap out of KASLR region on 5-level paging
acpi/nfit, x86/mce: Validate a MCE's address before using it
acpi/nfit, x86/mce: Handle only uncorrectable machine checks
x86/build: Remove -pipe from KBUILD_CFLAGS
x86/hyper-v: Fix indentation in hv_do_fast_hypercall16()
Documentation/x86: Fix typo in zero-page.txt
x86/hyper-v: Enable PIT shutdown quirk
clockevents/drivers/i8253: Add support for PIT shutdown quirk
According to Ted Ts'o ext4_getblk() called in ext4_xattr_inode_write()
should not return bh = NULL
The only time that bh could be NULL, then, would be in the case of
something really going wrong; a programming error elsewhere (perhaps a
wild pointer dereference) or I/O error causing on-disk file system
corruption (although that would be highly unlikely given that we had
*just* allocated the blocks and so the metadata blocks in question
probably would still be in the cache).
Fixes: e50e5129f384 ("ext4: xattr-in-inode support")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.13
We currently allow cloning a range from a file which includes the last
block of the file even if the file's size is not aligned to the block
size. This is fine and useful when the destination file has the same size,
but when it does not and the range ends somewhere in the middle of the
destination file, it leads to corruption because the bytes between the EOF
and the end of the block have undefined data (when there is support for
discard/trimming they have a value of 0x00).
Example:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ export foo_size=$((256 * 1024 + 100))
$ xfs_io -f -c "pwrite -S 0x3c 0 $foo_size" /mnt/foo
$ xfs_io -f -c "pwrite -S 0xb5 0 1M" /mnt/bar
$ xfs_io -c "reflink /mnt/foo 0 512K $foo_size" /mnt/bar
$ od -A d -t x1 /mnt/bar
0000000 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5
*
0524288 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c
*
0786528 3c 3c 3c 3c 00 00 00 00 00 00 00 00 00 00 00 00
0786544 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0790528 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5
*
1048576
The bytes in the range from 786532 (512Kb + 256Kb + 100 bytes) to 790527
(512Kb + 256Kb + 4Kb - 1) got corrupted, having now a value of 0x00 instead
of 0xb5.
This is similar to the problem we had for deduplication that got recently
fixed by commit de02b9f6bb65 ("Btrfs: fix data corruption when
deduplicating between different files").
Fix this by not allowing such operations to be performed and return the
errno -EINVAL to user space. This is what XFS is doing as well at the VFS
level. This change however now makes us return -EINVAL instead of
-EOPNOTSUPP for cases where the source range maps to an inline extent and
the destination range's end is smaller then the destination file's size,
since the detection of inline extents is done during the actual process of
dropping file extent items (at __btrfs_drop_extents()). Returning the
-EINVAL error is done early on and solely based on the input parameters
(offsets and length) and destination file's size. This makes us consistent
with XFS and anyone else supporting cloning since this case is now checked
at a higher level in the VFS and is where the -EINVAL will be returned
from starting with kernel 4.20 (the VFS changed was introduced in 4.20-rc1
by commit 07d19dc9fbe9 ("vfs: avoid problematic remapping requests into
partial EOF block"). So this change is more geared towards stable kernels,
as it's unlikely the new VFS checks get removed intentionally.
A test case for fstests follows soon, as well as an update to filter
existing tests that expect -EOPNOTSUPP to accept -EINVAL as well.
CC: <stable@vger.kernel.org> # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit b41d920acff8 ("kbuild: deb-pkg: split generating packaging
and build"), the build version of the kernel contained in a deb package
is too low by 1.
Prior to the bad commit, the kernel was built first, then the number
in .version file was read out, and written into the debian control file.
Now, the debian control file is created before the kernel is actually
compiled, which is causing the version number mismatch.
Let the mkdebian script pass KBUILD_BUILD_VERSION=${revision} to require
the build system to use the specified version number.
Fixes: b41d920acff8 ("kbuild: deb-pkg: split generating packaging and build")
Reported-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Doug Smythies <dsmythies@telus.net>