Pull vfs updates from Al Viro:
"Assorted patches from Miklos.
An interesting part here is /proc/mounts stuff..."
The "/proc/mounts stuff" is using a cursor for keeeping the location
data while traversing the mount listing.
Also probably worth noting is the addition of faccessat2(), which takes
an additional set of flags to specify how the lookup is done
(AT_EACCESS, AT_SYMLINK_NOFOLLOW, AT_EMPTY_PATH).
* 'from-miklos' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: add faccessat2 syscall
vfs: don't parse "silent" option
vfs: don't parse "posixacl" option
vfs: don't parse forbidden flags
statx: add mount_root
statx: add mount ID
statx: don't clear STATX_ATIME on SB_RDONLY
uapi: deprecate STATX_ALL
utimensat: AT_EMPTY_PATH support
vfs: split out access_override_creds()
proc/mounts: add cursor
aio: fix async fsync creds
vfs: allow unprivileged whiteout creation
Pull uaccess/csum updates from Al Viro:
"Regularize the sitation with uaccess checksum primitives:
- fold csum_partial_... into csum_and_copy_..._user()
- on x86 collapse several access_ok()/stac()/clac() into
user_access_begin()/user_access_end()"
* 'uaccess.csum' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
default csum_and_copy_to_user(): don't bother with access_ok()
take the dummy csum_and_copy_from_user() into net/checksum.h
arm: switch to csum_and_copy_from_user()
sh32: convert to csum_and_copy_from_user()
m68k: convert to csum_and_copy_from_user()
xtensa: switch to providing csum_and_copy_from_user()
sparc: switch to providing csum_and_copy_from_user()
parisc: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
alpha: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
ia64: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()
x86: switch 32bit csum_and_copy_to_user() to user_access_{begin,end}()
x86: switch both 32bit and 64bit to providing csum_and_copy_from_user()
x86_64: csum_..._copy_..._user(): switch to unsafe_..._user()
get rid of csum_partial_copy_to_user()
- Several Mac fixes,
- Defconfig updates,
- Minor cleanups and fixes.
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Merge tag 'm68k-for-v5.8-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
Pull m68k updates from Geert Uytterhoeven:
- several Mac fixes
- defconfig updates
- minor cleanups and fixes
* tag 'm68k-for-v5.8-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k: tools: Replace zero-length array with flexible-array member
m68k: Add missing __user annotation in get_user()
m68k: mac: Avoid stuck ISM IOP interrupt on Quadra 900/950
m68k: mac: Remove misleading comment
m68k: mac: Don't call via_flush_cache() on Mac IIfx
m68k: defconfig: Update defconfigs for v5.7-rc1
m68k: amiga: config: Replace zero-length array with flexible-array member
m68k: amiga: config: Mark expected switch fall-through
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200521185707.GA3661@embeddedor
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
The ptr is a pointer to userspace memory. So we need annotate it with
__user otherwise we may get sparse warnings like:
drivers/vhost/vhost.c:1603:13: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected void const *__gu_ptr @@ got unsigned int [noderef] [usertypvoid const *__gu_ptr @@
drivers/vhost/vhost.c:1603:13: sparse: expected void const *__gu_ptr
drivers/vhost/vhost.c:1603:13: sparse: got unsigned int [noderef] [usertype] <asn:1> *idxp
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20200520065750.8401-1-jasowang@redhat.com
Fixes: 7124330dab ("m68k/uaccess: Revive 64-bit get_user()")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
On a Quadra 900/950, the ISM IOP IRQ output pin is connected to an
edge-triggered input on VIA2. It is theoretically possible that this
signal could fail to produce the expected VIA2 interrupt.
The two IOP interrupt flags can be asserted in any order but the logic
in iop_ism_irq() does not allow for that. In particular, INT0 can be
asserted right after INT0 is checked and before INT1 is cleared.
Such an interrupt would produce no new edge and VIA2 would detect no
further interrupts from the IOP. Avoid this by looping over the INT0/1
handlers so an edge can be produced.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Cc: Joshua Thompson <funaho@jurai.org>
Link: https://lore.kernel.org/r/bfbb71db52c5e162d3afa25a28fc5d535ca87138.1589949122.git.fthain@telegraphics.com.au
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
POSIX defines faccessat() as having a fourth "flags" argument, while the
linux syscall doesn't have it. Glibc tries to emulate AT_EACCESS and
AT_SYMLINK_NOFOLLOW, but AT_EACCESS emulation is broken.
Add a new faccessat(2) syscall with the added flags argument and implement
both flags.
The value of AT_EACCESS is defined in glibc headers to be the same as
AT_REMOVEDIR. Use this value for the kernel interface as well, together
with the explanatory comment.
Also add AT_EMPTY_PATH support, which is not documented by POSIX, but can
be useful and is trivial to implement.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
- Enable modular build of Bare UDP Encapsulation, exFAT filesystem
support, and lockup and min heap test modules,
- Remove CONFIG_NF_TABLES_SET=m (removed in commit e32a4dc651
("netfilter: nf_tables: make sets built-in")),
- Disable CONFIG_VHOST_MENU (should default to n).
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20200413104153.30517-1-geert@linux-m68k.org
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200420181401.GA32172@embeddedor
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Mark switch cases where we are expecting to fall through.
This patch fixes the following warning (Building: allmodconfig m68k):
arch/m68k/amiga/config.c: In function ‘amiga_identify’:
./arch/m68k/include/asm/amigahw.h:42:50: warning: this statement may fall through [-Wimplicit-fallthrough=]
#define AMIGAHW_SET(name) (amiga_hw_present.name = 1)
~~~~~~~~~~~~~~~~~~~~~~~^~~~
arch/m68k/amiga/config.c:223:3: note: in expansion of macro ‘AMIGAHW_SET’
AMIGAHW_SET(PCMCIA);
^~~~~~~~~~~
arch/m68k/amiga/config.c:224:2: note: here
case AMI_500:
^~~~
Replace the existing /* fall through */ comments and fix the issue above
by using the new pseudo-keyword fallthrough;
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/14ff577604d25243c8a897f851b436ba87ae87cb.1585264062.git.gustavo@embeddedor.com
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
The cleanup in commit 630f289b71 ("asm-generic: make more
kernel-space headers mandatory") did not take into account the recently
added line for hardirq.h in commit acc45648b9 ("m68k: Switch to
asm-generic/hardirq.h"), leading to the following message during the
build:
scripts/Makefile.asm-generic:25: redundant generic-y found in arch/m68k/include/asm/Kbuild: hardirq.h
Fix this by dropping the now redundant line.
Fixes: 630f289b71 ("asm-generic: make more kernel-space headers mandatory")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently there are many platforms that dont enable ARCH_HAS_PTE_SPECIAL
but required to define quite similar fallback stubs for special page
table entry helpers such as pte_special() and pte_mkspecial(), as they
get build in generic MM without a config check. This creates two
generic fallback stub definitions for these helpers, eliminating much
code duplication.
mips platform has a special case where pte_special() and pte_mkspecial()
visibility is wider than what ARCH_HAS_PTE_SPECIAL enablement requires.
This restricts those symbol visibility in order to avoid redefinitions
which is now exposed through this new generic stubs and subsequent build
failure. arm platform set_pte_at() definition needs to be moved into a
C file just to prevent a build failure.
[anshuman.khandual@arm.com: use defined(CONFIG_ARCH_HAS_PTE_SPECIAL) in mips per Thomas]
Link: http://lkml.kernel.org/r/1583851924-21603-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Guo Ren <guoren@kernel.org> [csky]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Stafford Horne <shorne@gmail.com> [openrisc]
Acked-by: Helge Deller <deller@gmx.de> [parisc]
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: http://lkml.kernel.org/r/1583802551-15406-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are many platforms with exact same value for VM_DATA_DEFAULT_FLAGS
This creates a default value for VM_DATA_DEFAULT_FLAGS in line with the
existing VM_STACK_DEFAULT_FLAGS. While here, also define some more
macros with standard VMA access flag combinations that are used
frequently across many platforms. Apart from simplification, this
reduces code duplication as well.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Chris Zankel <chris@zankel.net>
Link: http://lkml.kernel.org/r/1583391014-8170-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull m68knommu update from Greg Ungerer:
"Only a single commit, to remove all use of the obsolete setup_irq()
calls within the m68knommu architecture code"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
m68k: Replace setup_irq() by request_irq()
It is unlikely that an inaccessible VMA without required permission flags
will get a page fault. Hence lets just append unlikely() directive to
such checks in order to improve performance while also standardizing it
across various platforms.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Link: http://lkml.kernel.org/r/1582525304-32113-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here are 3 SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your current
tree, that should be trivial to handle (one file modified by two things,
one file deleted.)
All 3 of these have been in linux-next for a while, with no reported
issues other than the merge conflict.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
update changing all our txt files to rst ones. Excluding that, we
have the usual driver updates (qla2xxx, ufs, lpfc, zfcp, ibmvfc,
pm80xx, aacraid), a treewide update for scnprintf and some other minor
updates. The major core update is Hannes moving functions out of the
aacraid driver and into the core.
Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI updates from James Bottomley:
"This series has a huge amount of churn because it pulls in Mauro's doc
update changing all our txt files to rst ones.
Excluding that, we have the usual driver updates (qla2xxx, ufs, lpfc,
zfcp, ibmvfc, pm80xx, aacraid), a treewide update for scnprintf and
some other minor updates.
The major core change is Hannes moving functions out of the aacraid
driver and into the core"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (223 commits)
scsi: aic7xxx: aic97xx: Remove FreeBSD-specific code
scsi: ufs: Do not rely on prefetched data
scsi: dc395x: remove dc395x_bios_param
scsi: libiscsi: Fix error count for active session
scsi: hpsa: correct race condition in offload enabled
scsi: message: fusion: Replace zero-length array with flexible-array member
scsi: qedi: Add PCI shutdown handler support
scsi: qedi: Add MFW error recovery process
scsi: ufs: Enable block layer runtime PM for well-known logical units
scsi: ufs-qcom: Override devfreq parameters
scsi: ufshcd: Let vendor override devfreq parameters
scsi: ufshcd: Update the set frequency to devfreq
scsi: ufs: Resume ufs host before accessing ufs device
scsi: ufs-mediatek: customize the delay for enabling host
scsi: ufs: make HCE polling more compact to improve initialization latency
scsi: ufs: allow custom delay prior to host enabling
scsi: ufs-mediatek: use common delay function
scsi: ufs: introduce common and flexible delay function
scsi: ufs: use an enum for host capabilities
scsi: ufs: fix uninitialized tx_lanes in ufshcd_disable_tx_lcc()
...
The idea comes from a discussion between Linus and Andrea [1].
Before this patch we only allow a page fault to retry once. We achieved
this by clearing the FAULT_FLAG_ALLOW_RETRY flag when doing
handle_mm_fault() the second time. This was majorly used to avoid
unexpected starvation of the system by looping over forever to handle the
page fault on a single page. However that should hardly happen, and after
all for each code path to return a VM_FAULT_RETRY we'll first wait for a
condition (during which time we should possibly yield the cpu) to happen
before VM_FAULT_RETRY is really returned.
This patch removes the restriction by keeping the FAULT_FLAG_ALLOW_RETRY
flag when we receive VM_FAULT_RETRY. It means that the page fault handler
now can retry the page fault for multiple times if necessary without the
need to generate another page fault event. Meanwhile we still keep the
FAULT_FLAG_TRIED flag so page fault handler can still identify whether a
page fault is the first attempt or not.
Then we'll have these combinations of fault flags (only considering
ALLOW_RETRY flag and TRIED flag):
- ALLOW_RETRY and !TRIED: this means the page fault allows to
retry, and this is the first try
- ALLOW_RETRY and TRIED: this means the page fault allows to
retry, and this is not the first try
- !ALLOW_RETRY and !TRIED: this means the page fault does not allow
to retry at all
- !ALLOW_RETRY and TRIED: this is forbidden and should never be used
In existing code we have multiple places that has taken special care of
the first condition above by checking against (fault_flags &
FAULT_FLAG_ALLOW_RETRY). This patch introduces a simple helper to detect
the first retry of a page fault by checking against both (fault_flags &
FAULT_FLAG_ALLOW_RETRY) and !(fault_flag & FAULT_FLAG_TRIED) because now
even the 2nd try will have the ALLOW_RETRY set, then use that helper in
all existing special paths. One example is in __lock_page_or_retry(), now
we'll drop the mmap_sem only in the first attempt of page fault and we'll
keep it in follow up retries, so old locking behavior will be retained.
This will be a nice enhancement for current code [2] at the same time a
supporting material for the future userfaultfd-writeprotect work, since in
that work there will always be an explicit userfault writeprotect retry
for protected pages, and if that cannot resolve the page fault (e.g., when
userfaultfd-writeprotect is used in conjunction with swapped pages) then
we'll possibly need a 3rd retry of the page fault. It might also benefit
other potential users who will have similar requirement like userfault
write-protection.
GUP code is not touched yet and will be covered in follow up patch.
Please read the thread below for more information.
[1] https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/
[2] https://lore.kernel.org/lkml/20181230154648.GB9832@redhat.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160246.9790-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Although there're tons of arch-specific page fault handlers, most of them
are still sharing the same initial value of the page fault flags. Say,
merely all of the page fault handlers would allow the fault to be retried,
and they also allow the fault to respond to SIGKILL.
Let's define a default value for the fault flags to replace those initial
page fault flags that were copied over. With this, it'll be far easier to
introduce new fault flag that can be used by all the architectures instead
of touching all the archs.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160238.9694-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For most architectures, we've got a quick path to detect fatal signal
after a handle_mm_fault(). Introduce a helper for that quick path.
It cleans the current codes a bit so we don't need to duplicate the same
check across archs. More importantly, this will be an unified place that
we handle the signal immediately right after an interrupted page fault, so
it'll be much easier for us if we want to change the behavior of handling
signals later on for all the archs.
Note that currently only part of the archs are using this new helper,
because some archs have their own way to handle signals. In the follow up
patches, we'll try to apply this helper to all the rest of archs.
Another note is that the "regs" parameter in the new helper is not used
yet. It'll be used very soon. Now we kept it in this patch only to avoid
touching all the archs again in the follow up patches.
[peterx@redhat.com: fix sparse warnings]
Link: http://lkml.kernel.org/r/20200311145921.GD479302@xz-x1
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220155353.8676-4-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change a header to mandatory-y if both of the following are met:
[1] At least one architecture (except um) specifies it as generic-y in
arch/*/include/asm/Kbuild
[2] Every architecture (except um) either has its own implementation
(arch/*/include/asm/*.h) or specifies it as generic-y in
arch/*/include/asm/Kbuild
This commit was generated by the following shell script.
----------------------------------->8-----------------------------------
arches=$(cd arch; ls -1 | sed -e '/Kconfig/d' -e '/um/d')
tmpfile=$(mktemp)
grep "^mandatory-y +=" include/asm-generic/Kbuild > $tmpfile
find arch -path 'arch/*/include/asm/Kbuild' |
xargs sed -n 's/^generic-y += \(.*\)/\1/p' | sort -u |
while read header
do
mandatory=yes
for arch in $arches
do
if ! grep -q "generic-y += $header" arch/$arch/include/asm/Kbuild &&
! [ -f arch/$arch/include/asm/$header ]; then
mandatory=no
break
fi
done
if [ "$mandatory" = yes ]; then
echo "mandatory-y += $header" >> $tmpfile
for arch in $arches
do
sed -i "/generic-y += $header/d" arch/$arch/include/asm/Kbuild
done
fi
done
sed -i '/^mandatory-y +=/d' include/asm-generic/Kbuild
LANG=C sort $tmpfile >> include/asm-generic/Kbuild
----------------------------------->8-----------------------------------
One obvious benefit is the diff stat:
25 files changed, 52 insertions(+), 557 deletions(-)
It is tedious to list generic-y for each arch that needs it.
So, mandatory-y works like a fallback default (by just wrapping
asm-generic one) when arch does not have a specific header
implementation.
See the following commits:
def3f7cefea1b39bae16
It is tedious to convert headers one by one, so I processed by a shell
script.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: http://lkml.kernel.org/r/20200210175452.5030-1-masahiroy@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull locking updates from Ingo Molnar:
"The main changes in this cycle were:
- Continued user-access cleanups in the futex code.
- percpu-rwsem rewrite that uses its own waitqueue and atomic_t
instead of an embedded rwsem. This addresses a couple of
weaknesses, but the primary motivation was complications on the -rt
kernel.
- Introduce raw lock nesting detection on lockdep
(CONFIG_PROVE_RAW_LOCK_NESTING=y), document the raw_lock vs. normal
lock differences. This too originates from -rt.
- Reuse lockdep zapped chain_hlocks entries, to conserve RAM
footprint on distro-ish kernels running into the "BUG:
MAX_LOCKDEP_CHAIN_HLOCKS too low!" depletion of the lockdep
chain-entries pool.
- Misc cleanups, smaller fixes and enhancements - see the changelog
for details"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t
thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t
Documentation/locking/locktypes: Minor copy editor fixes
Documentation/locking/locktypes: Further clarifications and wordsmithing
m68knommu: Remove mm.h include from uaccess_no.h
x86: get rid of user_atomic_cmpxchg_inatomic()
generic arch_futex_atomic_op_inuser() doesn't need access_ok()
x86: don't reload after cmpxchg in unsafe_atomic_op2() loop
x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end()
objtool: whitelist __sanitizer_cov_trace_switch()
[parisc, s390, sparc64] no need for access_ok() in futex handling
sh: no need of access_ok() in arch_futex_atomic_op_inuser()
futex: arch_futex_atomic_op_inuser() calling conventions change
completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all()
lockdep: Add posixtimer context tracing bits
lockdep: Annotate irq_work
lockdep: Add hrtimer context tracing bits
lockdep: Introduce wait-type checks
completion: Use simple wait queues
sched/swait: Prepare usage in completions
...
In file included
from include/linux/huge_mm.h:8,
from include/linux/mm.h:567,
from arch/m68k/include/asm/uaccess_no.h:8,
from arch/m68k/include/asm/uaccess.h:3,
from include/linux/uaccess.h:11,
from include/linux/sched/task.h:11,
from include/linux/sched/signal.h:9,
from include/linux/rcuwait.h:6,
from include/linux/percpu-rwsem.h:7,
from kernel/locking/percpu-rwsem.c:6:
include/linux/fs.h:1422:29: error: array type has incomplete element type 'struct percpu_rw_semaphore'
1422 | struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS];
Removing the include of linux/mm.h from the uaccess header solves the problem
and various build tests of nommu configurations still work.
Fixes: 80fbaf1c3f ("rcuwait: Add @state argument to rcuwait_wait_event()")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lkml.kernel.org/r/87fte1qzh0.fsf@nanos.tec.linutronix.de
Current make_request based drivers use either blk_alloc_queue_node or
blk_alloc_queue to allocate a queue, and then set up the make_request_fn
function pointer and a few parameters using the blk_queue_make_request
helper. Simplify this by passing the make_request pointer to
blk_alloc_queue, and while at it merge the _node variant into the main
helper by always passing a node_id, and remove the superfluous gfp_mask
parameter. A lower-level __blk_alloc_queue is kept for the blk-mq case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.
Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.
Hence replace setup_irq() by request_irq().
[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos
Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
- Drop CONFIG_NETFILTER_XT_MATCH_PHYSDEV=m (depends on
BRIDGE_NETFILTER, which is disabled by default since commit
98bda63e20 ("net: disable BRIDGE_NETFILTER by default")),
- Enable modular build of the WireGuard secure network tunnel,
- Drop CONFIG_CRYPTO_LIB_{BLAKE2S,CHACHA20POLY1305,CURVE25519}=m
(auto-enabled by CONFIG_WIREGUARD).
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Classic m68k with MMU was converted to generic hardirqs a long time ago,
and there are no longer include dependency issues preventing the direct
use of asm-generic/hardirq.h.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200112174854.2726-1-geert@linux-m68k.org
Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
$ sed -e 's/^ /\t/' -i */Kconfig
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20191120133721.12178-1-krzk@kernel.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This kernel configuration is basically enabling/disabling sr driver quirks
detection. While these quirks are for fairly rare devices (very old CD
burners, and a glucometer), the additional detection of these models is a
very minimal amount of code.
The logic behind the quirks is always built into the sr driver.
This also removes the config from all the defconfig files that are enabling
this already.
Link: https://lore.kernel.org/r/20200223191144.726-1-flameeyes@flameeyes.com
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
To match what we did to the Motorola MMU routines, change the ColdFire
pgalloc.
The result is that ColdFire and Sun3 pgalloc are actually very similar
and could conceivably be unified.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.995781825@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Also iterate the PMD tables to populate the PTE table allocator. This
also fully replaces the previous zero_pgtable hack.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.938797587@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
In addition to the PGD/PMD table size (128*4) add a PTE table size
(64*4) to the table allocator. This completely removes the pte-table
overhead compared to the old code, even for dense tables.
Notes:
- the allocator gained a list_empty() check to deal with there not
being any pages at all.
- the free mask is extended to cover more than the 8 bits required
for the (512 byte) PGD/PMD tables.
- NR_PAGETABLE accounting is restored.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.882175409@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
With the new page-table layout, using full (4k) pages for (256 byte)
pte-tables is immensely wastefull. Move the pte-tables over to the
same allocator already used for the (512 byte) higher level tables
(pgd/pmd).
This reduces the pte-table waste from 15x to 2x.
Due to no longer being bound to 16 consecutive tables, this might
actually already be more efficient than the old code for sparse
tables.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.825295149@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
With the PTE-tables now only being 256 bytes, allocating a full page
for them is a giant waste. Start by improving the boot time allocator
such that init_mm initialization will at least have optimal memory
density.
Much thanks to Will Deacon in help with debugging and ferreting out
lost information on these dusty MMUs.
Notes:
- _TABLE_MASK is reduced to account for the shorter (256 byte)
alignment of pte-tables, per the manual, table entries should only
ever have state in the low 4 bits (Used,WrProt,Desc1,Desc0) so it is
still longer than strictly required. (Thanks Will!!!)
- Also use kernel_page_table() for the 020/030 zero_pgtable case and
consequently remove the zero_pgtable init hack (will fix up later).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.768263973@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
The Motorola 68xxx MMUs, 040 (and later) have a fixed 7,7,{5,6}
page-table setup, where the last depends on the page-size selected (8k
vs 4k resp.), and head.S selects 4K pages. For 030 (and earlier) we
explicitly program 7,7,6 and 4K pages in %tc.
However, the current code implements this mightily weird. What it does
is group 16 of those (6 bit) pte tables into one 4k page to not waste
space. The down-side is that that forces pmd_t to be a 16-tuple
pointing to consecutive pte tables.
This breaks the generic code which assumes READ_ONCE(*pmd) will be
word sized.
Therefore implement a straight forward 7,7,6 3 level page-table setup,
with the addition (for 020/030) of (partial) large-page support. For
now this increases the memory footprint for pte-tables 15 fold.
Tested with ARAnyM/68040 emulation.
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.711478295@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Only the Motorola MMU makes use of this allocator, it is a waste of
.text to include it for Sun3/ColdFire. Also, this is going to avoid
build issues when we're going to make it more Motorola specific.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.654652162@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Seeing how there are 5 copies of this magic code, one of which is
unexplainably different, unify and document things.
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.597688427@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
I also notice that building for m5475evb_defconfig with vanilla v5.5
triggers this scary looking warning due to a mismatch between the pgd
size and the (8k!) page size:
| In function 'pgd_alloc.isra.111',
| inlined from 'mm_alloc_pgd' at kernel/fork.c:634:12,
| inlined from 'mm_init.isra.112' at kernel/fork.c:1043:6:
| ./arch/m68k/include/asm/string.h:72:25: warning: '__builtin_memcpy' forming offset [4097, 8192] is out of the bounds [0, 4096] of object 'kernel_pg_dir' with type 'pgd_t[1024]' {aka 'struct <anonymous>[1024]'} [-Warray-bounds]
| #define memcpy(d, s, n) __builtin_memcpy(d, s, n)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
| ./arch/m68k/include/asm/mcf_pgalloc.h:93:2: note: in expansion of macro 'memcpy'
| memcpy(new_pgd, swapper_pg_dir, PAGE_SIZE);
| ^~~~~~
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.540057688@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Since ColdFire V4e is a software TLB-miss architecture, there is no
need for page-tables to be mapped uncached. Remove this stray
nocache_page() dance, which isn't paired with a cache_page() and looks
like a copy/paste/edit fail.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.481739981@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Pull m68knommu updates from Greg Ungerer:
"A couple of changes:
- remove old CONFIG options from the m68knommu defconfig files
- fix a warning in the m68k non-MMU get_user() macro"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
m68knommu: fix memcpy() out of bounds warning in get_user()
m68k: configs: Cleanup old Kconfig IO scheduler options
Newer versions of gcc are giving warnings in the non-MMU m68k version
of the get_user() macro:
./arch/m68k/include/asm/string.h:72:25: warning: ‘__builtin_memcpy’ forming offset [3, 4] is out of the bounds [0, 2] of object ‘__gu_val’ with type ‘short unsigned int’ [-Warray-bounds]
The warnings are generated when smaller sized variables are used as the
result of user space pointers to larger values. For example a
short/2-byte variable stores the result of a user space int (4-byte)
pointer. The warning is in the 8-byte branch of get_user() - even
though that branch is not the taken branch in the warning cases.
Refactor the 8-byte branch of get_user() so that it uses a correctly
formed union type to read and write the source and destination objects.
Keep using the memcpy() just in case the user space pointer is not
naturaly aligned (not required for ColdFire, but needed for early
68000).
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
CONFIG_IOSCHED_DEADLINE and CONFIG_IOSCHED_CFQ are gone since
commit f382fb0bce ("block: remove legacy IO schedulers").
The IOSCHED_DEADLINE was replaced by MQ_IOSCHED_DEADLINE and it will be
now enabled by default (along with MQ_IOSCHED_KYBER).
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
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Merge tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull thread management updates from Christian Brauner:
"Sargun Dhillon over the last cycle has worked on the pidfd_getfd()
syscall.
This syscall allows for the retrieval of file descriptors of a process
based on its pidfd. A task needs to have ptrace_may_access()
permissions with PTRACE_MODE_ATTACH_REALCREDS (suggested by Oleg and
Andy) on the target.
One of the main use-cases is in combination with seccomp's user
notification feature. As a reminder, seccomp's user notification
feature was made available in v5.0. It allows a task to retrieve a
file descriptor for its seccomp filter. The file descriptor is usually
handed of to a more privileged supervising process. The supervisor can
then listen for syscall events caught by the seccomp filter of the
supervisee and perform actions in lieu of the supervisee, usually
emulating syscalls. pidfd_getfd() is needed to expand its uses.
There are currently two major users that wait on pidfd_getfd() and one
future user:
- Netflix, Sargun said, is working on a service mesh where users
should be able to connect to a dns-based VIP. When a user connects
to e.g. 1.2.3.4:80 that runs e.g. service "foo" they will be
redirected to an envoy process. This service mesh uses seccomp user
notifications and pidfd to intercept all connect calls and instead
of connecting them to 1.2.3.4:80 connects them to e.g.
127.0.0.1:8080.
- LXD uses the seccomp notifier heavily to intercept and emulate
mknod() and mount() syscalls for unprivileged containers/processes.
With pidfd_getfd() more uses-cases e.g. bridging socket connections
will be possible.
- The patchset has also seen some interest from the browser corner.
Right now, Firefox is using a SECCOMP_RET_TRAP sandbox managed by a
broker process. In the future glibc will start blocking all signals
during dlopen() rendering this type of sandbox impossible. Hence,
in the future Firefox will switch to a seccomp-user-nofication
based sandbox which also makes use of file descriptor retrieval.
The thread for this can be found at
https://sourceware.org/ml/libc-alpha/2019-12/msg00079.html
With pidfd_getfd() it is e.g. possible to bridge socket connections
for the supervisee (binding to a privileged port) and taking actions
on file descriptors on behalf of the supervisee in general.
Sargun's first version was using an ioctl on pidfds but various people
pushed for it to be a proper syscall which he duely implemented as
well over various review cycles. Selftests are of course included.
I've also added instructions how to deal with merge conflicts below.
There's also a small fix coming from the kernel mentee project to
correctly annotate struct sighand_struct with __rcu to fix various
sparse warnings. We've received a few more such fixes and even though
they are mostly trivial I've decided to postpone them until after -rc1
since they came in rather late and I don't want to risk introducing
build warnings.
Finally, there's a new prctl() command PR_{G,S}ET_IO_FLUSHER which is
needed to avoid allocation recursions triggerable by storage drivers
that have userspace parts that run in the IO path (e.g. dm-multipath,
iscsi, etc). These allocation recursions deadlock the device.
The new prctl() allows such privileged userspace components to avoid
allocation recursions by setting the PF_MEMALLOC_NOIO and
PF_LESS_THROTTLE flags. The patch carries the necessary acks from the
relevant maintainers and is routed here as part of prctl()
thread-management."
* tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim
sched.h: Annotate sighand_struct with __rcu
test: Add test for pidfd getfd
arch: wire up pidfd_getfd syscall
pid: Implement pidfd_getfd syscall
vfs, fdtable: Add fget_task helper
