While the ggtt vma are protected by their object lifetime, the list
continues until it hits a non-ggtt vma, and that vma is not protected
and may be freed as we inspect it. Hence, we require the obj->vma.lock
to protect the list as we iterate.
An example of forgetting to hold the obj->vma.lock is
[1642834.464973] general protection fault, probably for non-canonical address 0xdead000000000122: 0000 [#1] SMP PTI
[1642834.464977] CPU: 3 PID: 1954 Comm: Xorg Not tainted 5.6.0-300.fc32.x86_64 #1
[1642834.464979] Hardware name: LENOVO 20ARS25701/20ARS25701, BIOS GJET94WW (2.44 ) 09/14/2017
[1642834.465021] RIP: 0010:i915_gem_object_set_tiling+0x2c0/0x3e0 [i915]
[1642834.465024] Code: 8b 84 24 18 01 00 00 f6 c4 80 74 59 49 8b 94 24 a0 00 00 00 49 8b 84 24 e0 00 00 00 49 8b 74 24 10 48 8b 92 30 01 00 00 89 c7 <80> ba 0a 06 00 00 03 0f 87 86 00 00 00 ba 00 00 08 00 b9 00 00 10
[1642834.465025] RSP: 0018:ffffa98780c77d60 EFLAGS: 00010282
[1642834.465028] RAX: ffff8d232bfb2578 RBX: 0000000000000002 RCX: ffff8d25873a0000
[1642834.465029] RDX: dead000000000122 RSI: fffff0af8ac6e408 RDI: 000000002bfb2578
[1642834.465030] RBP: ffff8d25873a0000 R08: ffff8d252bfb5638 R09: 0000000000000000
[1642834.465031] R10: 0000000000000000 R11: ffff8d252bfb5640 R12: ffffa987801cb8f8
[1642834.465032] R13: 0000000000001000 R14: ffff8d233e972e50 R15: ffff8d233e972d00
[1642834.465034] FS: 00007f6a3d327f00(0000) GS:ffff8d25926c0000(0000) knlGS:0000000000000000
[1642834.465036] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1642834.465037] CR2: 00007f6a2064d000 CR3: 00000002fb57c001 CR4: 00000000001606e0
[1642834.465038] Call Trace:
[1642834.465083] i915_gem_set_tiling_ioctl+0x122/0x230 [i915]
[1642834.465121] ? i915_gem_object_set_tiling+0x3e0/0x3e0 [i915]
[1642834.465151] drm_ioctl_kernel+0x86/0xd0 [drm]
[1642834.465156] ? avc_has_perm+0x3b/0x160
[1642834.465178] drm_ioctl+0x206/0x390 [drm]
[1642834.465216] ? i915_gem_object_set_tiling+0x3e0/0x3e0 [i915]
[1642834.465221] ? selinux_file_ioctl+0x122/0x1c0
[1642834.465226] ? __do_munmap+0x24b/0x4d0
[1642834.465231] ksys_ioctl+0x82/0xc0
[1642834.465235] __x64_sys_ioctl+0x16/0x20
[1642834.465238] do_syscall_64+0x5b/0xf0
[1642834.465243] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[1642834.465245] RIP: 0033:0x7f6a3d7b047b
[1642834.465247] Code: 0f 1e fa 48 8b 05 1d aa 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ed a9 0c 00 f7 d8 64 89 01 48
[1642834.465249] RSP: 002b:00007ffe71adba28 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[1642834.465251] RAX: ffffffffffffffda RBX: 000055f99048fa40 RCX: 00007f6a3d7b047b
[1642834.465253] RDX: 00007ffe71adba30 RSI: 00000000c0106461 RDI: 000000000000000e
[1642834.465254] RBP: 0000000000000002 R08: 000055f98f3f1798 R09: 0000000000000002
[1642834.465255] R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000080
[1642834.465257] R13: 000055f98f3f1690 R14: 00000000c0106461 R15: 00007ffe71adba30
Now to take the spinlock during the list iteration, we need to break it
down into two phases. In the first phase under the lock, we cannot sleep
and so must defer the actual work to a second list, protected by the
ggtt->mutex.
We also need to hold the spinlock during creation of a new vma to
serialise with updates of the tiling on the object.
Reported-by: Dave Airlie <airlied@redhat.com>
Fixes: 2850748ef8 ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422072805.17340-1-chris@chris-wilson.co.uk
(cherry picked from commit cb593e5d2b)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
igt_ppgtt_pin_update() invokes i915_gem_context_get_vm_rcu(), which
returns a reference of the i915_address_space object to "vm" with
increased refcount.
When igt_ppgtt_pin_update() returns, "vm" becomes invalid, so the
refcount should be decreased to keep refcount balanced.
The reference counting issue happens in two exception handling paths of
igt_ppgtt_pin_update(). When i915_gem_object_create_internal() returns
IS_ERR, the refcnt increased by i915_gem_context_get_vm_rcu() is not
decreased, causing a refcnt leak.
Fix this issue by jumping to "out_vm" label when
i915_gem_object_create_internal() returns IS_ERR.
Fixes: a4e7ccdac3 ("drm/i915: Move context management under GEM")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1587361342-83494-1-git-send-email-xiyuyang19@fudan.edu.cn
(cherry picked from commit e07c7606a0)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Fix the warning caused by enabling the autosectionlabel extension in the
kernel Sphinx build:
Documentation/gpu/i915.rst:610: WARNING: duplicate label
gpu/i915:layout, other instance in Documentation/gpu/i915.rst
The autosectionlabel extension adds labels to each section title for
cross-referencing, but forbids identical section titles in a
document. With kernel-doc, this includes sections titles in the included
kernel-doc comments.
In the warning message, Sphinx is unable to reference the labels in
their true locations in the kernel-doc comments in source. In this case,
there's "Layout" sections in both gt/intel_workarounds.c and
i915_reg.h. Rename the section in the latter to "File Layout".
Fixes: 58ad30cf91 ("docs: fix reference to core-api/namespaces.rst")
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417130109.12791-1-jani.nikula@intel.com
(cherry picked from commit 27be41de45)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Right now dp.regs.dp_tp_ctl/status are only set during the encoder
pre_enable() hook, what is causing all reads and writes to those
registers to go to offset 0x0 before pre_enable() is executed.
So if i915 takes the BIOS state and don't do a modeset any following
link retraing will fail.
In the case that i915 needs to do a modeset, the DDI disable sequence
will write to a wrong register not disabling DP 'Transport Enable' in
DP_TP_CTL, making a HDMI modeset in the same port/transcoder to
not light up the monitor.
So here for GENs older than 12, that have those registers fixed at
port offset range it is loading at encoder/port init while for GEN12
it will keep setting it at encoder pre_enable() and during HW state
readout.
Fixes: 4444df6e20 ("drm/i915/tgl: move DP_TP_* to transcoder")
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414230442.262092-1-jose.souza@intel.com
(cherry picked from commit edcb9028d6)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
It is wrong to block the user thread in the next poll when OA data is
already available which could not fit in the user buffer provided in
the previous read. In several cases the exact user buffer size is not
known. Blocking user space in poll can lead to data loss when the
buffer size used is smaller than the available data.
This change fixes this issue and allows user space to read all OA data
even when using a buffer size smaller than the available data using
multiple non-blocking reads rather than staying blocked in poll till
the next timer interrupt.
v2: Fix ret value for blocking reads (Umesh)
v3: Mistake during patch send (Ashutosh)
v4: Remove -EAGAIN from comment (Umesh)
v5: Improve condition for clearing pollin and return (Lionel)
v6: Improve blocking read loop and other cleanups (Lionel)
v7: Added Cc stable
Testcase: igt/perf/polling-small-buf
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200403010120.3067-1-ashutosh.dixit@intel.com
(cherry-picked from commit 6352219c39)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This sorts the actual field names too, potentially causing even more
chaos and confusion at merge time if you have edited the MAINTAINERS
file. But the end result is a more consistent layout, and hopefully
it's a one-time pain minimized by doing this just before the -rc1
release.
This was entirely scripted:
./scripts/parse-maintainers.pl --input=MAINTAINERS --output=MAINTAINERS --order
Requested-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They are all supposed to be sorted, but people who add new entries don't
always know the alphabet. Plus sometimes the entry names get edited,
and people don't then re-order the entry.
Let's see how painful this will be for merging purposes (the MAINTAINERS
file is often edited in various different trees), but Joe claims there's
relatively few patches in -next that touch this, and doing it just
before -rc1 is likely the best time. Fingers crossed.
This was scripted with
/scripts/parse-maintainers.pl --input=MAINTAINERS --output=MAINTAINERS
but then I also ended up manually upper-casing a few entry names that
stood out when looking at the end result.
Requested-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 fixes from Thomas Gleixner:
"A set of three patches to fix the fallout of the newly added split
lock detection feature.
It addressed the case where a KVM guest triggers a split lock #AC and
KVM reinjects it into the guest which is not prepared to handle it.
Add proper sanity checks which prevent the unconditional injection
into the guest and handles the #AC on the host side in the same way as
user space detections are handled. Depending on the detection mode it
either warns and disables detection for the task or kills the task if
the mode is set to fatal"
* tag 'x86-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest
KVM: x86: Emulate split-lock access as a write in emulator
x86/split_lock: Provide handle_guest_split_lock()
Pull time(keeping) updates from Thomas Gleixner:
- Fix the time_for_children symlink in /proc/$PID/ so it properly
reflects that it part of the 'time' namespace
- Add the missing userns limit for the allowed number of time
namespaces, which was half defined but the actual array member was
not added. This went unnoticed as the array has an exessive empty
member at the end but introduced a user visible regression as the
output was corrupted.
- Prevent further silent ucount corruption by adding a BUILD_BUG_ON()
to catch half updated data.
* tag 'timers-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ucount: Make sure ucounts in /proc/sys/user don't regress again
time/namespace: Add max_time_namespaces ucount
time/namespace: Fix time_for_children symlink
Pull scheduler fixes/updates from Thomas Gleixner:
- Deduplicate the average computations in the scheduler core and the
fair class code.
- Fix a raise between runtime distribution and assignement which can
cause exceeding the quota by up to 70%.
- Prevent negative results in the imbalanace calculation
- Remove a stale warning in the workqueue code which can be triggered
since the call site was moved out of preempt disabled code. It's a
false positive.
- Deduplicate the print macros for procfs
- Add the ucmap values to the SCHED_DEBUG procfs output for completness
* tag 'sched-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/debug: Add task uclamp values to SCHED_DEBUG procfs
sched/debug: Factor out printing formats into common macros
sched/debug: Remove redundant macro define
sched/core: Remove unused rq::last_load_update_tick
workqueue: Remove the warning in wq_worker_sleeping()
sched/fair: Fix negative imbalance in imbalance calculation
sched/fair: Fix race between runtime distribution and assignment
sched/fair: Align rq->avg_idle and rq->avg_scan_cost
Pull perf fixes from Thomas Gleixner:
"Three fixes/updates for perf:
- Fix the perf event cgroup tracking which tries to track the cgroup
even for disabled events.
- Add Ice Lake server support for uncore events
- Disable pagefaults when retrieving the physical address in the
sampling code"
* tag 'perf-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Disable page faults when getting phys address
perf/x86/intel/uncore: Add Ice Lake server uncore support
perf/cgroup: Correct indirection in perf_less_group_idx()
perf/core: Fix event cgroup tracking
Pull locking fixes from Thomas Gleixner:
"Three small fixes/updates for the locking core code:
- Plug a task struct reference leak in the percpu rswem
implementation.
- Document the refcount interaction with PID_MAX_LIMIT
- Improve the 'invalid wait context' data dump in lockdep so it
contains all information which is required to decode the problem"
* tag 'locking-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Improve 'invalid wait context' splat
locking/refcount: Document interaction with PID_MAX_LIMIT
locking/percpu-rwsem: Fix a task_struct refcount
Pull cifs fixes from Steve French:
"Ten cifs/smb fixes:
- five RDMA (smbdirect) related fixes
- add experimental support for swap over SMB3 mounts
- also a fix which improves performance of signed connections"
* tag '5.7-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
smb3: enable swap on SMB3 mounts
smb3: change noisy error message to FYI
smb3: smbdirect support can be configured by default
cifs: smbd: Do not schedule work to send immediate packet on every receive
cifs: smbd: Properly process errors on ib_post_send
cifs: Allocate crypto structures on the fly for calculating signatures of incoming packets
cifs: smbd: Update receive credits before sending and deal with credits roll back on failure before sending
cifs: smbd: Check send queue size before posting a send
cifs: smbd: Merge code to track pending packets
cifs: ignore cached share root handle closing errors
Pull NFS client bugfix from Trond Myklebust:
"Fix an RCU read lock leakage in pnfs_alloc_ds_commits_list()"
* tag 'nfs-for-5.7-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
pNFS: Fix RCU lock leakage
Pull dma-mapping fixes from Christoph Hellwig:
- fix an integer truncation in dma_direct_get_required_mask
(Kishon Vijay Abraham)
- fix the display of dma mapping types (Grygorii Strashko)
* tag 'dma-mapping-5.7-1' of git://git.infradead.org/users/hch/dma-mapping:
dma-debug: fix displaying of dma allocation type
dma-direct: fix data truncation in dma_direct_get_required_mask()
Pull more Kbuild updates from Masahiro Yamada:
- raise minimum supported binutils version to 2.23
- remove old CONFIG_AS_* macros that we know binutils >= 2.23 supports
- move remaining CONFIG_AS_* tests to Kconfig from Makefile
- enable -Wtautological-compare warnings to catch more issues
- do not support GCC plugins for GCC <= 4.7
- fix various breakages of 'make xconfig'
- include the linker version used for linking the kernel into
LINUX_COMPILER, which is used for the banner, and also exposed to
/proc/version
- link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y, which
allows us to remove the lib-ksyms.o workaround, and to solve the last
known issue of the LLVM linker
- add dummy tools in scripts/dummy-tools/ to enable all compiler tests
in Kconfig, which will be useful for distro maintainers
- support the single switch, LLVM=1 to use Clang and all LLVM utilities
instead of GCC and Binutils.
- support LLVM_IAS=1 to enable the integrated assembler, which is still
experimental
* tag 'kbuild-v5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (36 commits)
kbuild: fix comment about missing include guard detection
kbuild: support LLVM=1 to switch the default tools to Clang/LLVM
kbuild: replace AS=clang with LLVM_IAS=1
kbuild: add dummy toolchains to enable all cc-option etc. in Kconfig
kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y
MIPS: fw: arc: add __weak to prom_meminit and prom_free_prom_memory
kbuild: remove -I$(srctree)/tools/include from scripts/Makefile
kbuild: do not pass $(KBUILD_CFLAGS) to scripts/mkcompile_h
Documentation/llvm: fix the name of llvm-size
kbuild: mkcompile_h: Include $LD version in /proc/version
kconfig: qconf: Fix a few alignment issues
kconfig: qconf: remove some old bogus TODOs
kconfig: qconf: fix support for the split view mode
kconfig: qconf: fix the content of the main widget
kconfig: qconf: Change title for the item window
kconfig: qconf: clean deprecated warnings
gcc-plugins: drop support for GCC <= 4.7
kbuild: Enable -Wtautological-compare
x86: update AS_* macros to binutils >=2.23, supporting ADX and AVX2
crypto: x86 - clean up poly1305-x86_64-cryptogams.S by 'make clean'
...
I do not longer work for credativ Germany.
Please, use my private email address instead.
This is for the case when people want to CC me on
patches sent from my old business email address.
Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Another brown paper bag moment. pnfs_alloc_ds_commits_list() is leaking
the RCU lock.
Fixes: a9901899b6 ("pNFS: Add infrastructure for cleaning up per-layout commit structures")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Two types of #AC can be generated in Intel CPUs:
1. legacy alignment check #AC
2. split lock #AC
Reflect #AC back into the guest if the guest has legacy alignment checks
enabled or if split lock detection is disabled.
If the #AC is not a legacy one and split lock detection is enabled, then
invoke handle_guest_split_lock() which will either warn and disable split
lock detection for this task or force SIGBUS on it.
[ tglx: Switch it to handle_guest_split_lock() and rename the misnamed
helper function. ]
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200410115517.176308876@linutronix.de
Without at least minimal handling for split lock detection induced #AC,
VMX will just run into the same problem as the VMWare hypervisor, which
was reported by Kenneth.
It will inject the #AC blindly into the guest whether the guest is
prepared or not.
Provide a function for guest mode which acts depending on the host
SLD mode. If mode == sld_warn, treat it like user space, i.e. emit a
warning, disable SLD and mark the task accordingly. Otherwise force
SIGBUS.
[ bp: Add a !CPU_SUP_INTEL stub for handle_guest_split_lock(). ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200410115516.978037132@linutronix.de
Link: https://lkml.kernel.org/r/20200402123258.895628824@linutronix.de
Merge yet more updates from Andrew Morton:
- Almost all of the rest of MM (memcg, slab-generic, slab, pagealloc,
gup, hugetlb, pagemap, memremap)
- Various other things (hfs, ocfs2, kmod, misc, seqfile)
* akpm: (34 commits)
ipc/util.c: sysvipc_find_ipc() should increase position index
kernel/gcov/fs.c: gcov_seq_next() should increase position index
fs/seq_file.c: seq_read(): add info message about buggy .next functions
drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings
change email address for Pali Rohár
selftests: kmod: test disabling module autoloading
selftests: kmod: fix handling test numbers above 9
docs: admin-guide: document the kernel.modprobe sysctl
fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
kmod: make request_module() return an error when autoloading is disabled
mm/memremap: set caching mode for PCI P2PDMA memory to WC
mm/memory_hotplug: add pgprot_t to mhp_params
powerpc/mm: thread pgprot_t through create_section_mapping()
x86/mm: introduce __set_memory_prot()
x86/mm: thread pgprot_t through init_memory_mapping()
mm/memory_hotplug: rename mhp_restrictions to mhp_params
mm/memory_hotplug: drop the flags field from struct mhp_restrictions
mm/special: create generic fallbacks for pte_special() and pte_mkspecial()
mm/vma: introduce VM_ACCESS_FLAGS
mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS
...
Pull orangefs updates from Mike Marshall:
"A fix and two cleanups.
Fix:
- Christoph Hellwig noticed that some logic I added to
orangefs_file_read_iter introduced a race condition, so he sent a
reversion patch. I had to modify his patch since reverting at this
point broke Orangefs.
Cleanups:
- Christoph Hellwig noticed that we were doing some unnecessary work
in orangefs_flush, so he sent in a patch that removed the un-needed
code.
- Al Viro told me he had trouble building Orangefs. Orangefs should
be easy to build, even for Al :-).
I looked back at the test server build notes in orangefs.txt, just
in case that's where the trouble really is, and found a couple of
typos and made a couple of clarifications"
* tag 'for-linus-5.7-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux:
orangefs: clarify build steps for test server in orangefs.txt
orangefs: don't mess with I_DIRTY_TIMES in orangefs_flush
orangefs: get rid of knob code...
Pull xtensa updates from Max Filippov:
- replace setup_irq() by request_irq()
- cosmetic fixes in xtensa Kconfig and boot/Makefile
* tag 'xtensa-20200410' of git://github.com/jcmvbkbc/linux-xtensa:
arch/xtensa: fix grammar in Kconfig help text
xtensa: remove meaningless export ccflags-y
xtensa: replace setup_irq() by request_irq()
Pull more xen updates from Juergen Gross:
- two cleanups
- fix a boot regression introduced in this merge window
- fix wrong use of memory allocation flags
* tag 'for-linus-5.7-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen: fix booting 32-bit pv guest
x86/xen: make xen_pvmmu_arch_setup() static
xen/blkfront: fix memory allocation flags in blkfront_setup_indirect()
xen: Use evtchn_type_t as a type for event channels
Patch series "seq_file .next functions should increase position index".
In Aug 2018 NeilBrown noticed commit 1f4aace60b ("fs/seq_file.c:
simplify seq_file iteration code and interface")
"Some ->next functions do not increment *pos when they return NULL...
Note that such ->next functions are buggy and should be fixed. A simple
demonstration is dd if=/proc/swaps bs=1000 skip=1 Choose any block size
larger than the size of /proc/swaps. This will always show the whole
last line of /proc/swaps"
Described problem is still actual. If you make lseek into middle of
last output line following read will output end of last line and whole
last line once again.
$ dd if=/proc/swaps bs=1 # usual output
Filename Type Size Used Priority
/dev/dm-0 partition 4194812 97536 -2
104+0 records in
104+0 records out
104 bytes copied
$ dd if=/proc/swaps bs=40 skip=1 # last line was generated twice
dd: /proc/swaps: cannot skip to specified offset
v/dm-0 partition 4194812 97536 -2
/dev/dm-0 partition 4194812 97536 -2
3+1 records in
3+1 records out
131 bytes copied
There are lot of other affected files, I've found 30+ including
/proc/net/ip_tables_matches and /proc/sysvipc/*
I've sent patches into maillists of affected subsystems already, this
patch-set fixes the problem in files related to pstore, tracing, gcov,
sysvipc and other subsystems processed via linux-kernel@ mailing list
directly
https://bugzilla.kernel.org/show_bug.cgi?id=206283
This patch (of 4):
Add debug code to seq_read() to detect missed or out-of-tree incorrect
.next seq_file functions.
[akpm@linux-foundation.org: s/pr_info/pr_info_ratelimited/, per Qian Cai]
https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: NeilBrown <neilb@suse.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Waiman Long <longman@redhat.com>
Link: http://lkml.kernel.org/r/244674e5-760c-86bd-d08a-047042881748@virtuozzo.com
Link: http://lkml.kernel.org/r/7c24087c-e280-e580-5b0c-0cdaeb14cd18@virtuozzo.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "module autoloading fixes and cleanups", v5.
This series fixes a bug where request_module() was reporting success to
kernel code when module autoloading had been completely disabled via
'echo > /proc/sys/kernel/modprobe'.
It also addresses the issues raised on the original thread
(https://lkml.kernel.org/lkml/20200310223731.126894-1-ebiggers@kernel.org/T/#u)
bydocumenting the modprobe sysctl, adding a self-test for the empty path
case, and downgrading a user-reachable WARN_ONCE().
This patch (of 4):
It's long been possible to disable kernel module autoloading completely
(while still allowing manual module insertion) by setting
/proc/sys/kernel/modprobe to the empty string.
This can be preferable to setting it to a nonexistent file since it
avoids the overhead of an attempted execve(), avoids potential
deadlocks, and avoids the call to security_kernel_module_request() and
thus on SELinux-based systems eliminates the need to write SELinux rules
to dontaudit module_request.
However, when module autoloading is disabled in this way,
request_module() returns 0. This is broken because callers expect 0 to
mean that the module was successfully loaded.
Apparently this was never noticed because this method of disabling
module autoloading isn't used much, and also most callers don't use the
return value of request_module() since it's always necessary to check
whether the module registered its functionality or not anyway.
But improperly returning 0 can indeed confuse a few callers, for example
get_fs_type() in fs/filesystems.c where it causes a WARNING to be hit:
if (!fs && (request_module("fs-%.*s", len, name) == 0)) {
fs = __get_fs_type(name, len);
WARN_ONCE(!fs, "request_module fs-%.*s succeeded, but still no fs?\n", len, name);
}
This is easily reproduced with:
echo > /proc/sys/kernel/modprobe
mount -t NONEXISTENT none /
It causes:
request_module fs-NONEXISTENT succeeded, but still no fs?
WARNING: CPU: 1 PID: 1106 at fs/filesystems.c:275 get_fs_type+0xd6/0xf0
[...]
This should actually use pr_warn_once() rather than WARN_ONCE(), since
it's also user-reachable if userspace immediately unloads the module.
Regardless, request_module() should correctly return an error when it
fails. So let's make it return -ENOENT, which matches the error when
the modprobe binary doesn't exist.
I've also sent patches to document and test this case.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Ben Hutchings <benh@debian.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200310223731.126894-1-ebiggers@kernel.org
Link: http://lkml.kernel.org/r/20200312202552.241885-1-ebiggers@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
