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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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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Pull more btrfs updates from David Sterba:
"We have queued a few more fixes (error handling, log replay,
softlockup) and the rest is SPDX updates that touche almost all files
so the diffstat is long"
* tag 'for-4.17-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: Only check first key for committed tree blocks
btrfs: add SPDX header to Kconfig
btrfs: replace GPL boilerplate by SPDX -- sources
btrfs: replace GPL boilerplate by SPDX -- headers
Btrfs: fix loss of prealloc extents past i_size after fsync log replay
Btrfs: clean up resources during umount after trans is aborted
btrfs: Fix possible softlock on single core machines
Btrfs: bail out on error during replay_dir_deletes
Btrfs: fix NULL pointer dereference in log_dir_items
Pull cifs fixes from Steve French:
"SMB3 fixes, a few for stable, and some important cleanup work from
Ronnie of the smb3 transport code"
* tag '4.17-rc1SMB3-Fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: change validate_buf to validate_iov
cifs: remove rfc1002 hardcoded constants from cifs_discard_remaining_data()
cifs: Change SMB2_open to return an iov for the error parameter
cifs: add resp_buf_size to the mid_q_entry structure
smb3.11: replace a 4 with server->vals->header_preamble_size
cifs: replace a 4 with server->vals->header_preamble_size
cifs: add pdu_size to the TCP_Server_Info structure
SMB311: Improve checking of negotiate security contexts
SMB3: Fix length checking of SMB3.11 negotiate request
CIFS: add ONCE flag for cifs_dbg type
cifs: Use ULL suffix for 64-bit constant
SMB3: Log at least once if tree connect fails during reconnect
cifs: smb2pdu: Fix potential NULL pointer dereference
When looping btrfs/074 with many cpus (>= 8), it's possible to trigger
kernel warning due to first key verification:
[ 4239.523446] WARNING: CPU: 5 PID: 2381 at fs/btrfs/disk-io.c:460 btree_read_extent_buffer_pages+0x1ad/0x210
[ 4239.523830] Modules linked in:
[ 4239.524630] RIP: 0010:btree_read_extent_buffer_pages+0x1ad/0x210
[ 4239.527101] Call Trace:
[ 4239.527251] read_tree_block+0x42/0x70
[ 4239.527434] read_node_slot+0xd2/0x110
[ 4239.527632] push_leaf_right+0xad/0x1b0
[ 4239.527809] split_leaf+0x4ea/0x700
[ 4239.527988] ? leaf_space_used+0xbc/0xe0
[ 4239.528192] ? btrfs_set_lock_blocking_rw+0x99/0xb0
[ 4239.528416] btrfs_search_slot+0x8cc/0xa40
[ 4239.528605] btrfs_insert_empty_items+0x71/0xc0
[ 4239.528798] __btrfs_run_delayed_refs+0xa98/0x1680
[ 4239.529013] btrfs_run_delayed_refs+0x10b/0x1b0
[ 4239.529205] btrfs_commit_transaction+0x33/0xaf0
[ 4239.529445] ? start_transaction+0xa8/0x4f0
[ 4239.529630] btrfs_alloc_data_chunk_ondemand+0x1b0/0x4e0
[ 4239.529833] btrfs_check_data_free_space+0x54/0xa0
[ 4239.530045] btrfs_delalloc_reserve_space+0x25/0x70
[ 4239.531907] btrfs_direct_IO+0x233/0x3d0
[ 4239.532098] generic_file_direct_write+0xcb/0x170
[ 4239.532296] btrfs_file_write_iter+0x2bb/0x5f4
[ 4239.532491] aio_write+0xe2/0x180
[ 4239.532669] ? lock_acquire+0xac/0x1e0
[ 4239.532839] ? __might_fault+0x3e/0x90
[ 4239.533032] do_io_submit+0x594/0x860
[ 4239.533223] ? do_io_submit+0x594/0x860
[ 4239.533398] SyS_io_submit+0x10/0x20
[ 4239.533560] ? SyS_io_submit+0x10/0x20
[ 4239.533729] do_syscall_64+0x75/0x1d0
[ 4239.533979] entry_SYSCALL_64_after_hwframe+0x42/0xb7
[ 4239.534182] RIP: 0033:0x7f8519741697
The problem here is, at btree_read_extent_buffer_pages() we don't have
acquired read/write lock on that extent buffer, only basic info like
level/bytenr is reliable.
So race condition leads to such false alert.
However in current call site, it's impossible to acquire proper lock
without race window.
To fix the problem, we only verify first key for committed tree blocks
(whose generation is no larger than fs_info->last_trans_committed), so
the content of such tree blocks will not change and there is no need to
get read/write lock.
Reported-by: Nikolay Borisov <nborisov@suse.com>
Fixes: 581c1760415c ("btrfs: Validate child tree block's level and first key")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull SCSI fixes from James Bottomley:
"This is a set of minor (and safe changes) that didn't make the initial
pull request plus some bug fixes.
The status handling code is actually a running regression from the
previous merge window which had an incomplete fix (now reverted) and
most of the remaining bug fixes are for problems older than the
current merge window"
[ Side note: this merge also takes the base kernel git repository to 6+
million objects for the first time. Technically we hit it a couple of
merges ago already if you count all the tag objects, but now it
reaches 6M+ objects reachable from HEAD.
I was joking around that that's when I should switch to 5.0, because
3.0 happened at the 2M mark, and 4.0 happened at 4M objects. But
probably not, even if numerology is about as good a reason as any.
- Linus ]
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: devinfo: Add Microsoft iSCSI target to 1024 sector blacklist
scsi: cxgb4i: silence overflow warning in t4_uld_rx_handler()
scsi: dpt_i2o: Use after free in I2ORESETCMD ioctl
scsi: core: Make scsi_result_to_blk_status() recognize CONDITION MET
scsi: core: Rename __scsi_error_from_host_byte() into scsi_result_to_blk_status()
Revert "scsi: core: return BLK_STS_OK for DID_OK in __scsi_error_from_host_byte()"
scsi: aacraid: Insure command thread is not recursively stopped
scsi: qla2xxx: Correct setting of SAM_STAT_CHECK_CONDITION
scsi: qla2xxx: correctly shift host byte
scsi: qla2xxx: Fix race condition between iocb timeout and initialisation
scsi: qla2xxx: Avoid double completion of abort command
scsi: qla2xxx: Fix small memory leak in qla2x00_probe_one on probe failure
scsi: scsi_dh: Don't look for NULL devices handlers by name
scsi: core: remove redundant assignment to shost->use_blk_mq
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull more Kbuild updates from Masahiro Yamada:
- pass HOSTLDFLAGS when compiling single .c host programs
- build genksyms lexer and parser files instead of using shipped
versions
- rename *-asn1.[ch] to *.asn1.[ch] for suffix consistency
- let the top .gitignore globally ignore artifacts generated by flex,
bison, and asn1_compiler
- let the top Makefile globally clean artifacts generated by flex,
bison, and asn1_compiler
- use safer .SECONDARY marker instead of .PRECIOUS to prevent
intermediate files from being removed
- support -fmacro-prefix-map option to make __FILE__ a relative path
- fix # escaping to prepare for the future GNU Make release
- clean up deb-pkg by using debian tools instead of handrolled
source/changes generation
- improve rpm-pkg portability by supporting kernel-install as a
fallback of new-kernel-pkg
- extend Kconfig listnewconfig target to provide more information
* tag 'kbuild-v4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: extend output of 'listnewconfig'
kbuild: rpm-pkg: use kernel-install as a fallback for new-kernel-pkg
Kbuild: fix # escaping in .cmd files for future Make
kbuild: deb-pkg: split generating packaging and build
kbuild: use -fmacro-prefix-map to make __FILE__ a relative path
kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers
kbuild: rename *-asn1.[ch] to *.asn1.[ch]
kbuild: clean up *-asn1.[ch] patterns from top-level Makefile
.gitignore: move *-asn1.[ch] patterns to the top-level .gitignore
kbuild: add %.dtb.S and %.dtb to 'targets' automatically
kbuild: add %.lex.c and %.tab.[ch] to 'targets' automatically
genksyms: generate lexer and parser during build instead of shipping
kbuild: clean up *.lex.c and *.tab.[ch] patterns from top-level Makefile
.gitignore: move *.lex.c *.tab.[ch] patterns to the top-level .gitignore
kbuild: use HOSTLDFLAGS for single .c executables
The Windows Server 2016 iSCSI target doesn't work with the Linux kernel
initiator since the kernel started sending larger requests by default,
nor does it implement the block limits VPD page. Apply the sector limit
workaround for these targets.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: KY Srinivasan <kys@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Add the
SPDX header.
Signed-off-by: David Sterba <dsterba@suse.com>
Pull x86 fixes from Thomas Gleixner:
"A set of fixes and updates for x86:
- Address a swiotlb regression which was caused by the recent DMA
rework and made driver fail because dma_direct_supported() returned
false
- Fix a signedness bug in the APIC ID validation which caused invalid
APIC IDs to be detected as valid thereby bloating the CPU possible
space.
- Fix inconsisten config dependcy/select magic for the MFD_CS5535
driver.
- Fix a corruption of the physical address space bits when encryption
has reduced the address space and late cpuinfo updates overwrite
the reduced bit information with the original value.
- Dominiks syscall rework which consolidates the architecture
specific syscall functions so all syscalls can be wrapped with the
same macros. This allows to switch x86/64 to struct pt_regs based
syscalls. Extend the clearing of user space controlled registers in
the entry patch to the lower registers"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Fix signedness bug in APIC ID validity checks
x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption
x86/olpc: Fix inconsistent MFD_CS5535 configuration
swiotlb: Use dma_direct_supported() for swiotlb_ops
syscalls/x86: Adapt syscall_wrapper.h to the new syscall stub naming convention
syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()
syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention
syscalls/core, syscalls/x86: Clean up syscall stub naming convention
syscalls/x86: Extend register clearing on syscall entry to lower registers
syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64
syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32
syscalls/core: Prepare CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y for compat syscalls
syscalls/x86: Use 'struct pt_regs' based syscall calling convention for 64-bit syscalls
syscalls/core: Introduce CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y
x86/syscalls: Don't pointlessly reload the system call number
x86/mm: Fix documentation of module mapping range with 4-level paging
x86/cpuid: Switch to 'static const' specifier
We at Red Hat/Fedora have generally tried to have a per file breakdown of
every config option we set. This makes it easy for us to add new options
when they are exposed and keep a changelog of why they were set.
A Fedora example is here:
https://src.fedoraproject.org/cgit/rpms/kernel.git/tree/configs/fedora/generic
Using various merge scripts, we build up a config file and run it through
'make listnewconfig' and 'make oldnoconfig'. The idea is to print out new
config options that haven't been manually set and use the default until
a patch is posted to set it properly.
To speed things up, it would be nice to make it easier to generate a
patch to post the default setting. The output of 'make listnewconfig'
has two issues that limit us:
- it doesn't provide the default value
- it doesn't provide the new 'choice' options that get flagged in
'oldconfig'
This patch extends 'listnewconfig' to address the above two issues.
This allows us to run a script
make listnewconfig | rhconfig-tool -o patches; git send-email patches/
The output of 'make listnewconfig':
CONFIG_NET_EMATCH_IPT
CONFIG_IPVLAN
CONFIG_ICE
CONFIG_NET_VENDOR_NI
CONFIG_IEEE802154_MCR20A
CONFIG_IR_IMON_DECODER
CONFIG_IR_IMON_RAW
The new output of 'make listnewconfig':
CONFIG_KERNEL_XZ=n
CONFIG_KERNEL_LZO=n
CONFIG_NET_EMATCH_IPT=n
CONFIG_IPVLAN=n
CONFIG_ICE=n
CONFIG_NET_VENDOR_NI=y
CONFIG_IEEE802154_MCR20A=n
CONFIG_IR_IMON_DECODER=n
CONFIG_IR_IMON_RAW=n
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Smatch marks skb->data as untrusted so it complains that there is a
potential overflow here:
drivers/scsi/cxgbi/cxgb4i/cxgb4i.c:2111 t4_uld_rx_handler()
error: buffer overflow 'cxgb4i_cplhandlers' 239 <= 255.
In this case, skb->data comes from the hardware or firmware so it's not
going to overflow unless there is a firmware bug.
[mkp: fixed braces]
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
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