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.
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Pull irq fixes from Thomas Gleixner:
"Two fixes for interrupt controller drivers:
- Skip IRQ_M_EXT entries in the device tree when initializing the
RISCV PLIC controller to avoid a double init attempt.
- Use the correct ITS list when issuing the VMOVP synchronization
command so the operation works only on the ITS instances which are
associated to a VM"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/sifive-plic: Skip contexts except supervisor in plic_init()
irqchip/gic-v3-its: Use the exact ITSList for VMOVP
Pull cifs fixes from Steve French:
"Seven cifs/smb3 fixes, including three for stable"
* tag '5.4-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
CIFS: Fix use after free of file info structures
CIFS: Fix retry mid list corruption on reconnects
cifs: Fix missed free operations
CIFS: avoid using MID 0xFFFF
cifs: clarify comment about timestamp granularity for old servers
cifs: Handle -EINPROGRESS only when noblockcnt is set
Pull the second lot of irqchip updates for 5.4 from Marc Zyngier:
- Sifive PLIC: force driver to skip non-relevant contexts
- GICv4: Don't send VMOVP commands to ITSs that don't have
this vPE mapped
Pull RISC-V fixes from Paul Walmsley:
"Several minor fixes and cleanups for v5.4-rc5:
- Three build fixes for various SPARSEMEM-related kernel
configurations
- Two cleanup patches for the kernel bug and breakpoint trap handler
code"
* tag 'riscv/for-v5.4-rc5-b' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: cleanup do_trap_break
riscv: cleanup <asm/bug.h>
riscv: Fix undefined reference to vmemmap_populate_basepages
riscv: Fix implicit declaration of 'page_to_section'
riscv: fix fs/proc/kcore.c compilation with sparsemem enabled
There's a deadlock that is possible and can easily be seen with
a test where multiple readers open/read/close of the same file
and a disruption occurs causing reconnect. The deadlock is due
a reader thread inside cifs_strict_readv calling down_read and
obtaining lock_sem, and then after reconnect inside
cifs_reopen_file calling down_read a second time. If in
between the two down_read calls, a down_write comes from
another process, deadlock occurs.
CPU0 CPU1
---- ----
cifs_strict_readv()
down_read(&cifsi->lock_sem);
_cifsFileInfo_put
OR
cifs_new_fileinfo
down_write(&cifsi->lock_sem);
cifs_reopen_file()
down_read(&cifsi->lock_sem);
Fix the above by changing all down_write(lock_sem) calls to
down_write_trylock(lock_sem)/msleep() loop, which in turn
makes the second down_read call benign since it will never
block behind the writer while holding lock_sem.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed--by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Modify plic_init() to skip .dts interrupt contexts other
than supervisor external interrupt.
The .dts entry for plic may specify multiple interrupt contexts.
For example, it may assign two entries IRQ_M_EXT and IRQ_S_EXT,
in that order, to the same interrupt controller. This patch
modifies plic_init() to skip the IRQ_M_EXT context since
IRQ_S_EXT is currently the only supported context.
If IRQ_M_EXT is not skipped, plic_init() will report "handler
already present for context" when it comes across the IRQ_S_EXT
context in the next iteration of its loop.
Without this patch, .dts would have to be edited to replace the
value of IRQ_M_EXT with -1 for it to be skipped.
Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Walmsley <paul.walmsley@sifive.com> # arch/riscv
Link: https://lkml.kernel.org/r/1571933503-21504-1-git-send-email-alan.mikhak@sifive.com
Pull MIPS fixes from Paul Burton:
"A few MIPS fixes:
- Fix VDSO time-related function behavior for systems where we need
to fall back to syscalls, but were instead returning bogus results.
- A fix to TLB exception handlers for Cavium Octeon systems where
they would inadvertently clobber the $1/$at register.
- A build fix for bcm63xx configurations.
- Switch to using my @kernel.org email address"
* tag 'mips_fixes_5.4_3' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: tlbex: Fix build_restore_pagemask KScratch restore
MIPS: bmips: mark exception vectors as char arrays
mips: vdso: Fix __arch_get_hw_counter()
MAINTAINERS: Use @kernel.org address for Paul Burton
If we always compile the get_break_insn_length inline function we can
remove the ifdefs and let dead code elimination take care of the warn
branch that is now unreadable because the report_bug stub always
returns BUG_TRAP_TYPE_BUG.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Currently the code assumes that if a file info entry belongs
to lists of open file handles of an inode and a tcon then
it has non-zero reference. The recent changes broke that
assumption when putting the last reference of the file info.
There may be a situation when a file is being deleted but
nothing prevents another thread to reference it again
and start using it. This happens because we do not hold
the inode list lock while checking the number of references
of the file info structure. Fix this by doing the proper
locking when doing the check.
Fixes: 487317c99477d ("cifs: add spinlock for the openFileList to cifsInodeInfo")
Fixes: cb248819d209d ("cifs: use cifsInodeInfo->open_file_lock while iterating to avoid a panic")
Cc: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull more Kbuild fixes from Masahiro Yamada:
- fix a bashism of setlocalversion
- do not use the too new --sort option of tar
* tag 'kbuild-fixes-v5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kheaders: substituting --sort in archive creation
scripts: setlocalversion: fix a bashism
kbuild: update comment about KBUILD_ALLDIRS
On a system without Single VMOVP support (say GITS_TYPER.VMOVP == 0),
we will map vPEs only on ITSs that will actually control interrupts
for the given VM. And when moving a vPE, the VMOVP command will be
issued only for those ITSs.
But when issuing VMOVPs we seemed fail to present the exact ITSList
to ITSs who are actually included in the synchronization operation.
The its_list_map we're currently using includes all ITSs in the system,
even though some of them don't have the corresponding vPE mapping at all.
Introduce get_its_list() to get the per-VM its_list_map, to indicate
which ITSs have vPE mappings for the given VM, and use this map as
the expected ITSList when building VMOVP. This is hopefully a performance
gain not to do some synchronization with those unsuspecting ITSs.
And initialize the whole command descriptor to zero at beginning, since
the seq_num and its_list should be RES0 when GITS_TYPER.VMOVP == 1.
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1571802386-2680-1-git-send-email-yuzenghui@huawei.com
Pull tty/serial driver fix from Greg KH:
"Here is a single tty/serial driver fix for 5.4-rc5 that resolves a
reported issue.
It has been in linux-next for a while with no problems"
* tag 'tty-5.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
8250-men-mcb: fix error checking when get_num_ports returns -ENODEV