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Rename psi_group structure member fields used for calculating psi totals
and averages for clear distinction between them and for trigger-related
fields that will be added by "psi: introduce psi monitor".
[surenb@google.com: v6]
Link: http://lkml.kernel.org/r/20190319235619.260832-4-surenb@google.com
Link: http://lkml.kernel.org/r/20190124211518.244221-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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psi_enable is not used outside of psi.c, make it static.
Link: http://lkml.kernel.org/r/20190319235619.260832-3-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "psi: pressure stall monitors", v6.
This is a respin of:
https://lwn.net/ml/linux-kernel/20190308184311.144521-1-surenb%40google.com/
Android is adopting psi to detect and remedy memory pressure that
results in stuttering and decreased responsiveness on mobile devices.
Psi gives us the stall information, but because we're dealing with
latencies in the millisecond range, periodically reading the pressure
files to detect stalls in a timely fashion is not feasible. Psi also
doesn't aggregate its averages at a high-enough frequency right now.
This patch series extends the psi interface such that users can
configure sensitive latency thresholds and use poll() and friends to be
notified when these are breached.
As high-frequency aggregation is costly, it implements an aggregation
method that is optimized for fast, short-interval averaging, and makes
the aggregation frequency adaptive, such that high-frequency updates
only happen while monitored stall events are actively occurring.
With these patches applied, Android can monitor for, and ward off,
mounting memory shortages before they cause problems for the user. For
example, using memory stall monitors in userspace low memory killer
daemon (lmkd) we can detect mounting pressure and kill less important
processes before device becomes visibly sluggish. In our memory stress
testing psi memory monitors produce roughly 10x less false positives
compared to vmpressure signals. Having ability to specify multiple
triggers for the same psi metric allows other parts of Android framework
to monitor memory state of the device and act accordingly.
The new interface is straight-forward. The user opens one of the
pressure files for writing and writes a trigger description into the
file descriptor that defines the stall state - some or full, and the
maximum stall time over a given window of time. E.g.:
/* Signal when stall time exceeds 100ms of a 1s window */
char trigger[] = "full 100000 1000000"
fd = open("/proc/pressure/memory")
write(fd, trigger, sizeof(trigger))
while (poll() >= 0) {
...
};
close(fd);
When the monitored stall state is entered, psi adapts its aggregation
frequency according to what the configured time window requires in order
to emit event signals in a timely fashion. Once the stalling subsides,
aggregation reverts back to normal.
The trigger is associated with the open file descriptor. To stop
monitoring, the user only needs to close the file descriptor and the
trigger is discarded.
Patches 1-6 prepare the psi code for polling support. Patch 7
implements the adaptive polling logic, the pressure growth detection
optimized for short intervals, and hooks up write() and poll() on the
pressure files.
The patches were developed in collaboration with Johannes Weiner.
This patch (of 7):
The psi monitoring patches will need to determine the same states as
record_times(). To avoid calculating them twice, maintain a state mask
that can be consulted cheaply. Do this in a separate patch to keep the
churn in the main feature patch at a minimum.
This adds 4-byte state_mask member into psi_group_cpu struct which
results in its first cacheline-aligned part becoming 52 bytes long. Add
explicit values to enumeration element counters that affect
psi_group_cpu struct size.
Link: http://lkml.kernel.org/r/20190124211518.244221-4-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The RCU reader uses rcu_dereference() inside rcu_read_lock critical
sections, so the writer shall use WRITE_ONCE. Just a cleanup, we still
rely on gcc to emit atomic writes in other places.
Link: http://lkml.kernel.org/r/20190325225636.11635-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The task structure is freed while get_mem_cgroup_from_mm() holds
rcu_read_lock() and dereferences mm->owner.
get_mem_cgroup_from_mm() failing fork()
---- ---
task = mm->owner
mm->owner = NULL;
free(task)
if (task) *task; /* use after free */
The fix consists in freeing the task with RCU also in the fork failure
case, exactly like it always happens for the regular exit(2) path. That
is enough to make the rcu_read_lock hold in get_mem_cgroup_from_mm()
(left side above) effective to avoid a use after free when dereferencing
the task structure.
An alternate possible fix would be to defer the delivery of the
userfaultfd contexts to the monitor until after fork() is guaranteed to
succeed. Such a change would require more changes because it would
create a strict ordering dependency where the uffd methods would need to
be called beyond the last potentially failing branch in order to be
safe. This solution as opposed only adds the dependency to common code
to set mm->owner to NULL and to free the task struct that was pointed by
mm->owner with RCU, if fork ends up failing. The userfaultfd methods
can still be called anywhere during the fork runtime and the monitor
will keep discarding orphaned "mm" coming from failed forks in userland.
This race condition couldn't trigger if CONFIG_MEMCG was set =n at build
time.
[aarcange@redhat.com: improve changelog, reduce #ifdefs per Michal]
Link: http://lkml.kernel.org/r/20190429035752.4508-1-aarcange@redhat.com
Link: http://lkml.kernel.org/r/20190325225636.11635-2-aarcange@redhat.com
Fixes: 893e26e61d04 ("userfaultfd: non-cooperative: Add fork() event")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: zhong jiang <zhongjiang@huawei.com>
Reported-by: syzbot+cbb52e396df3e565ab02@syzkaller.appspotmail.com
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: syzbot+cbb52e396df3e565ab02@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If the user downloads and applies patch-5.1.gz using patch(1), the x bit
on kernel/gen_ikh_data.sh is not set.
/bin/sh: 1: ./kernel/gen_ikh_data.sh: Permission denied
Fix this by using CONFIG_SHELL.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
Pull kgdb updates from Daniel Thompson:
"Mostly cleanups but there are also a couple of fixes for out-of-bounds
accesses (including a potential write to the byte before a static
buffer).
The main changes are:
- Fixes to those out-of-bounds access (empty string to configure test
module could write the byte before a buffer, high cpu counts could
read outside of per-cpu structures).
- Improvements to string handling problems picked up by new compiler
warnings and other static checks. Most are fixing benign issues
that can't be tickled without code changes but still reduce the wtf
factor a little.
- Tidy up the terminal output"
* tag 'kgdb-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
kdb: Fix bound check compiler warning
kdb: do a sanity check on the cpu in kdb_per_cpu()
kdb: Get rid of broken attempt to print CCVERSION in kdb summary
misc: kgdbts: fix out-of-bounds access in function param_set_kgdbts_var
kdb: kdb_support: replace strcpy() by strscpy()
gdbstub: Replace strcpy() by strscpy()
gdbstub: mark expected switch fall-throughs
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git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
- Use a separate table to store symbol types instead of hijacking
fields in struct Elf_Sym
- Trivial code cleanups
* tag 'modules-for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: add stubs for within_module functions
kallsyms: store type information in its own array
vmlinux.lds.h: drop unused __vermagic
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One of the biggest issues we face right now with picking LRU map over
regular hash table is that a map walk out of user space, for example,
to just dump the existing entries or to remove certain ones, will
completely mess up LRU eviction heuristics and wrong entries such
as just created ones will get evicted instead. The reason for this
is that we mark an entry as "in use" via bpf_lru_node_set_ref() from
system call lookup side as well. Thus upon walk, all entries are
being marked, so information of actual least recently used ones
are "lost".
In case of Cilium where it can be used (besides others) as a BPF
based connection tracker, this current behavior causes disruption
upon control plane changes that need to walk the map from user space
to evict certain entries. Discussion result from bpfconf [0] was that
we should simply just remove marking from system call side as no
good use case could be found where it's actually needed there.
Therefore this patch removes marking for regular LRU and per-CPU
flavor. If there ever should be a need in future, the behavior could
be selected via map creation flag, but due to mentioned reason we
avoid this here.
[0] http://vger.kernel.org/bpfconf.html
Fixes: 29ba732acbee ("bpf: Add BPF_MAP_TYPE_LRU_HASH")
Fixes: 8f8449384ec3 ("bpf: Add BPF_MAP_TYPE_LRU_PERCPU_HASH")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add a callback map_lookup_elem_sys_only() that map implementations
could use over map_lookup_elem() from system call side in case the
map implementation needs to handle the latter differently than from
the BPF data path. If map_lookup_elem_sys_only() is set, this will
be preferred pick for map lookups out of user space. This hook is
used in a follow-up fix for LRU map, but once development window
opens, we can convert other map types from map_lookup_elem() (here,
the one called upon BPF_MAP_LOOKUP_ELEM cmd is meant) over to use
the callback to simplify and clean up the latter.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge misc updates from Andrew Morton:
- a few misc things and hotfixes
- ocfs2
- almost all of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (139 commits)
kernel/memremap.c: remove the unused device_private_entry_fault() export
mm: delete find_get_entries_tag
mm/huge_memory.c: make __thp_get_unmapped_area static
mm/mprotect.c: fix compilation warning because of unused 'mm' variable
mm/page-writeback: introduce tracepoint for wait_on_page_writeback()
mm/vmscan: simplify trace_reclaim_flags and trace_shrink_flags
mm/Kconfig: update "Memory Model" help text
mm/vmscan.c: don't disable irq again when count pgrefill for memcg
mm: memblock: make keeping memblock memory opt-in rather than opt-out
hugetlbfs: always use address space in inode for resv_map pointer
mm/z3fold.c: support page migration
mm/z3fold.c: add structure for buddy handles
mm/z3fold.c: improve compression by extending search
mm/z3fold.c: introduce helper functions
mm/page_alloc.c: remove unnecessary parameter in rmqueue_pcplist
mm/hmm: add ARCH_HAS_HMM_MIRROR ARCH_HAS_HMM_DEVICE Kconfig
mm/vmscan.c: simplify shrink_inactive_list()
fs/sync.c: sync_file_range(2) may use WB_SYNC_ALL writeback
xen/privcmd-buf.c: convert to use vm_map_pages_zero()
xen/gntdev.c: convert to use vm_map_pages()
...
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This export has been entirely unused since it was added more than 1 1/2
years ago.
Link: http://lkml.kernel.org/r/20190429115535.12793-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Most architectures do not need the memblock memory after the page
allocator is initialized, but only few enable ARCH_DISCARD_MEMBLOCK in the
arch Kconfig.
Replacing ARCH_DISCARD_MEMBLOCK with ARCH_KEEP_MEMBLOCK and inverting the
logic makes it clear which architectures actually use memblock after
system initialization and skips the necessity to add ARCH_DISCARD_MEMBLOCK
to the architectures that are still missing that option.
Link: http://lkml.kernel.org/r/1556102150-32517-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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arch_add_memory, __add_pages take a want_memblock which controls whether
the newly added memory should get the sysfs memblock user API (e.g.
ZONE_DEVICE users do not want/need this interface). Some callers even
want to control where do we allocate the memmap from by configuring
altmap.
Add a more generic hotplug context for arch_add_memory and __add_pages.
struct mhp_restrictions contains flags which contains additional features
to be enabled by the memory hotplug (MHP_MEMBLOCK_API currently) and
altmap for alternative memmap allocator.
This patch shouldn't introduce any functional change.
[akpm@linux-foundation.org: build fix]
Link: http://lkml.kernel.org/r/20190408082633.2864-3-osalvador@suse.de
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This updates each existing invalidation to use the correct mmu notifier
event that represent what is happening to the CPU page table. See the
patch which introduced the events to see the rational behind this.
Link: http://lkml.kernel.org/r/20190326164747.24405-7-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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CPU page table update can happens for many reasons, not only as a result
of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as
a result of kernel activities (memory compression, reclaim, migration,
...).
Users of mmu notifier API track changes to the CPU page table and take
specific action for them. While current API only provide range of virtual
address affected by the change, not why the changes is happening.
This patchset do the initial mechanical convertion of all the places that
calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP
event as well as the vma if it is know (most invalidation happens against
a given vma). Passing down the vma allows the users of mmu notifier to
inspect the new vma page protection.
The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier
should assume that every for the range is going away when that event
happens. A latter patch do convert mm call path to use a more appropriate
events for each call.
This is done as 2 patches so that no call site is forgotten especialy
as it uses this following coccinelle patch:
%<----------------------------------------------------------------------
@@
identifier I1, I2, I3, I4;
@@
static inline void mmu_notifier_range_init(struct mmu_notifier_range *I1,
+enum mmu_notifier_event event,
+unsigned flags,
+struct vm_area_struct *vma,
struct mm_struct *I2, unsigned long I3, unsigned long I4) { ... }
@@
@@
-#define mmu_notifier_range_init(range, mm, start, end)
+#define mmu_notifier_range_init(range, event, flags, vma, mm, start, end)
@@
expression E1, E3, E4;
identifier I1;
@@
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, I1,
I1->vm_mm, E3, E4)
...>
@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(..., struct vm_area_struct *VMA, ...) {
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, VMA,
E2, E3, E4)
...> }
@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(...) {
struct vm_area_struct *VMA;
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, VMA,
E2, E3, E4)
...> }
@@
expression E1, E2, E3, E4;
identifier FN;
@@
FN(...) {
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, NULL,
E2, E3, E4)
...> }
---------------------------------------------------------------------->%
Applied with:
spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place
spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place
spatch --sp-file mmu-notifier.spatch --dir mm --in-place
Link: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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To facilitate additional options to get_user_pages_fast() change the
singular write parameter to be gup_flags.
This patch does not change any functionality. New functionality will
follow in subsequent patches.
Some of the get_user_pages_fast() call sites were unchanged because they
already passed FOLL_WRITE or 0 for the write parameter.
NOTE: It was suggested to change the ordering of the get_user_pages_fast()
arguments to ensure that callers were converted. This breaks the current
GUP call site convention of having the returned pages be the final
parameter. So the suggestion was rejected.
Link: http://lkml.kernel.org/r/20190328084422.29911-4-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-4-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Mike Marshall <hubcap@omnibond.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Userfaultfd can be misued to make it easier to exploit existing
use-after-free (and similar) bugs that might otherwise only make a
short window or race condition available. By using userfaultfd to
stall a kernel thread, a malicious program can keep some state that it
wrote, stable for an extended period, which it can then access using an
existing exploit. While it doesn't cause the exploit itself, and while
it's not the only thing that can stall a kernel thread when accessing a
memory location, it's one of the few that never needs privilege.
We can add a flag, allowing userfaultfd to be restricted, so that in
general it won't be useable by arbitrary user programs, but in
environments that require userfaultfd it can be turned back on.
Add a global sysctl knob "vm.unprivileged_userfaultfd" to control
whether userfaultfd is allowed by unprivileged users. When this is
set to zero, only privileged users (root user, or users with the
CAP_SYS_PTRACE capability) will be able to use the userfaultfd
syscalls.
Andrea said:
: The only difference between the bpf sysctl and the userfaultfd sysctl
: this way is that the bpf sysctl adds the CAP_SYS_ADMIN capability
: requirement, while userfaultfd adds the CAP_SYS_PTRACE requirement,
: because the userfaultfd monitor is more likely to need CAP_SYS_PTRACE
: already if it's doing other kind of tracking on processes runtime, in
: addition of userfaultfd. In other words both syscalls works only for
: root, when the two sysctl are opt-in set to 1.
[dgilbert@redhat.com: changelog additions]
[akpm@linux-foundation.org: documentation tweak, per Mike]
Link: http://lkml.kernel.org/r/20190319030722.12441-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
While validating new map we require the @start_data to be strictly less
than @end_data, which is fine for regular applications (this is why this
nit didn't trigger for that long). These members are set from executable
loaders such as elf handers, still it is pretty valid to have a loadable
data section with zero size in file, in such case the start_data is equal
to end_data once kernel loader finishes.
As a result when we're trying to restore such programs the procedure fails
and the kernel returns -EINVAL. From the image dump of a program:
| "mm_start_code": "0x400000",
| "mm_end_code": "0x8f5fb4",
| "mm_start_data": "0xf1bfb0",
| "mm_end_data": "0xf1bfb0",
Thus we need to change validate_prctl_map from strictly less to less or
equal operator use.
Link: http://lkml.kernel.org/r/20190408143554.GY1421@uranus.lan
Fixes: f606b77f1a9e3 ("prctl: PR_SET_MM -- introduce PR_SET_MM_MAP operation")
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Andrey Vagin <avagin@gmail.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The strncpy() function may leave the destination string buffer
unterminated, better use strscpy() instead.
This fixes the following warning with gcc 8.2:
kernel/debug/kdb/kdb_io.c: In function 'kdb_getstr':
kernel/debug/kdb/kdb_io.c:449:3: warning: 'strncpy' specified bound 256 equals destination size [-Wstringop-truncation]
strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Wenlin Kang <wenlin.kang@windriver.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
|
|
Both of them are not declared in the headers and not used outside
of bpf_trace.c file.
Fixes: a38d1107f937c ("bpf: support raw tracepoints in modules")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
synchronize_rcu() is fine when the rcu callbacks only need
to free memory (kfree_rcu() or direct kfree() call rcu call backs)
__dev_map_entry_free() is a bit more complex, so we need to make
sure that call queued __dev_map_entry_free() callbacks have completed.
sysbot report:
BUG: KASAN: use-after-free in dev_map_flush_old kernel/bpf/devmap.c:365
[inline]
BUG: KASAN: use-after-free in __dev_map_entry_free+0x2a8/0x300
kernel/bpf/devmap.c:379
Read of size 8 at addr ffff8801b8da38c8 by task ksoftirqd/1/18
CPU: 1 PID: 18 Comm: ksoftirqd/1 Not tainted 4.17.0+ #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b9/0x294 lib/dump_stack.c:113
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
dev_map_flush_old kernel/bpf/devmap.c:365 [inline]
__dev_map_entry_free+0x2a8/0x300 kernel/bpf/devmap.c:379
__rcu_reclaim kernel/rcu/rcu.h:178 [inline]
rcu_do_batch kernel/rcu/tree.c:2558 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2818 [inline]
__rcu_process_callbacks kernel/rcu/tree.c:2785 [inline]
rcu_process_callbacks+0xe9d/0x1760 kernel/rcu/tree.c:2802
__do_softirq+0x2e0/0xaf5 kernel/softirq.c:284
run_ksoftirqd+0x86/0x100 kernel/softirq.c:645
smpboot_thread_fn+0x417/0x870 kernel/smpboot.c:164
kthread+0x345/0x410 kernel/kthread.c:240
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
Allocated by task 6675:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620
kmalloc include/linux/slab.h:513 [inline]
kzalloc include/linux/slab.h:706 [inline]
dev_map_alloc+0x208/0x7f0 kernel/bpf/devmap.c:102
find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
map_create+0x393/0x1010 kernel/bpf/syscall.c:453
__do_sys_bpf kernel/bpf/syscall.c:2351 [inline]
__se_sys_bpf kernel/bpf/syscall.c:2328 [inline]
__x64_sys_bpf+0x303/0x510 kernel/bpf/syscall.c:2328
do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 26:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xd9/0x260 mm/slab.c:3813
dev_map_free+0x4fa/0x670 kernel/bpf/devmap.c:191
bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:262
process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153
worker_thread+0x181/0x13a0 kernel/workqueue.c:2296
kthread+0x345/0x410 kernel/kthread.c:240
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
The buggy address belongs to the object at ffff8801b8da37c0
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
512-byte region [ffff8801b8da37c0, ffff8801b8da39c0)
The buggy address belongs to the page:
page:ffffea0006e368c0 count:1 mapcount:0 mapping:ffff8801da800940
index:0xffff8801b8da3540
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea0007217b88 ffffea0006e30cc8 ffff8801da800940
raw: ffff8801b8da3540 ffff8801b8da3040 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801b8da3780: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8801b8da3800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801b8da3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801b8da3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801b8da3980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+457d3e2ffbcf31aee5c0@syzkaller.appspotmail.com
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
Pull networking fixes from David Miller:
"Fixes all over:
1) Netdev refcnt leak in nf_flow_table, from Taehee Yoo.
2) Fix RCU usage in nf_tables, from Florian Westphal.
3) Fix DSA build when NET_DSA_TAG_BRCM_PREPEND is not set, from Yue
Haibing.
4) Add missing page read/write ops to realtek driver, from Heiner
Kallweit.
5) Endianness fix in qrtr code, from Nicholas Mc Guire.
6) Fix various bugs in DSA_SKB_* macros, from Vladimir Oltean.
7) Several BPF documentation cures, from Quentin Monnet.
8) Fix undefined behavior in narrow load handling of BPF verifier,
from Krzesimir Nowak.
9) DMA ops crash in SGI Seeq driver due to not set netdev parent
device pointer, from Thomas Bogendoerfer.
10) Flow dissector has to disable preemption when invoking BPF
program, from Eric Dumazet"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (48 commits)
net: ethernet: stmmac: dwmac-sun8i: enable support of unicast filtering
net: ethernet: ti: netcp_ethss: fix build
flow_dissector: disable preemption around BPF calls
bonding: fix arp_validate toggling in active-backup mode
net: meson: fixup g12a glue ephy id
net: phy: realtek: Replace phy functions with non-locked version in rtl8211e_config_init()
net: seeq: fix crash caused by not set dev.parent
of_net: Fix missing of_find_device_by_node ref count drop
net: mvpp2: cls: Add missing NETIF_F_NTUPLE flag
bpf: fix undefined behavior in narrow load handling
libbpf: detect supported kernel BTF features and sanitize BTF
selftests: bpf: Add files generated after build to .gitignore
tools: bpf: synchronise BPF UAPI header with tools
bpf: fix minor issues in documentation for BPF helpers.
bpf: fix recurring typo in documentation for BPF helpers
bpf: fix script for generating man page on BPF helpers
bpf: add various test cases for backward jumps
net: dccp : proto: remove Unneeded variable "err"
net: dsa: Remove the now unused DSA_SKB_CB_COPY() macro
net: dsa: Remove dangerous DSA_SKB_CLONE() macro
...
|
|
Commit 31fd85816dbe ("bpf: permits narrower load from bpf program
context fields") made the verifier add AND instructions to clear the
unwanted bits with a mask when doing a narrow load. The mask is
computed with
(1 << size * 8) - 1
where "size" is the size of the narrow load. When doing a 4 byte load
of a an 8 byte field the verifier shifts the literal 1 by 32 places to
the left. This results in an overflow of a signed integer, which is an
undefined behavior. Typically, the computed mask was zero, so the
result of the narrow load ended up being zero too.
Cast the literal to long long to avoid overflows. Note that narrow
load of the 4 byte fields does not have the undefined behavior,
because the load size can only be either 1 or 2 bytes, so shifting 1
by 8 or 16 places will not overflow it. And reading 4 bytes would not
be a narrow load of a 4 bytes field.
Fixes: 31fd85816dbe ("bpf: permits narrower load from bpf program context fields")
Reviewed-by: Alban Crequy <alban@kinvolk.io>
Reviewed-by: Iago López Galeiras <iago@kinvolk.io>
Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
Cc: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
The "whichcpu" comes from argv[3]. The cpu_online() macro looks up the
cpu in a bitmap of online cpus, but if the value is too high then it
could read beyond the end of the bitmap and possibly Oops.
Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
|
|
If you drop into kdb and type "summary", it prints out a line that
says this:
ccversion CCVERSION
...and I don't mean that it actually prints out the version of the C
compiler. It literally prints out the string "CCVERSION".
The version of the C Compiler is already printed at boot up and it
doesn't seem useful to replicate this in kdb. Let's just delete it.
We can also delete the bit of the Makefile that called the C compiler
in an attempt to pass this into kdb. This will remove one extra call
to the C compiler at Makefile parse time and (very slightly) speed up
builds.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull gpio updates from Linus Walleij:
"This is the bulk of the GPIO changes for the v5.2 kernel cycle. A bit
later than usual because I was ironing out my own mistakes. I'm
holding some stuff back for the next kernel as a result, and this
should be a healthy and well tested batch.
Core changes:
- The gpiolib MMIO driver has been enhanced to handle two direction
registers, i.e. one register to set lines as input and one register
to set lines as output. It turns out some silicon engineer thinks
the ability to configure a line as input and output at the same
time makes sense, this can be debated but includes a lot of analog
electronics reasoning, and the registers are there and need to be
handled consistently. Unsurprisingly, we enforce the lines to be
either inputs or outputs in such schemes.
- Send in the proper argument value to .set_config() dispatched to
the pin control subsystem. Nobody used it before, now someone does,
so fix it to work as expected.
- The ACPI gpiolib portions can now handle pin bias setting (pull up
or pull down). This has been in the ACPI spec for years and we
finally have it properly integrated with Linux GPIOs. It was based
on an observation from Andy Schevchenko that Thomas Petazzoni's
changes to the core for biasing the PCA950x GPIO expander actually
happen to fit hand-in-glove with what the ACPI core needed. Such
nice synergies happen sometimes.
New drivers:
- A new driver for the Mellanox BlueField GPIO controller. This is
using 64bit MMIO registers and can configure lines as inputs and
outputs at the same time and after improving the MMIO library we
handle it just fine. Interesting.
- A new IXP4xx proper gpiochip driver with hierarchical interrupts
should be coming in from the ARM SoC tree as well.
Driver enhancements:
- The PCA053x driver handles the CAT9554 GPIO expander.
- The PCA053x driver handles the NXP PCAL6416 GPIO expander.
- Wake-up support on PCA053x GPIO lines.
- OMAP now does a nice asynchronous IRQ handling on wake-ups by
letting everything wake up on edges, and this makes runtime PM work
as expected too.
Misc:
- Several cleanups such as devres fixes.
- Get rid of some languager comstructs that cause problems when
compiling with LLVMs clang.
- Documentation review and update"
* tag 'gpio-v5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (85 commits)
gpio: Update documentation
docs: gpio: convert docs to ReST and rename to *.rst
gpio: sch: Remove write-only core_base
gpio: pxa: Make two symbols static
gpiolib: acpi: Respect pin bias setting
gpiolib: acpi: Add acpi_gpio_update_gpiod_lookup_flags() helper
gpiolib: acpi: Set pin value, based on bias, more accurately
gpiolib: acpi: Change type of dflags
gpiolib: Introduce GPIO_LOOKUP_FLAGS_DEFAULT
gpiolib: Make use of enum gpio_lookup_flags consistent
gpiolib: Indent entry values of enum gpio_lookup_flags
gpio: pca953x: add support for pca6416
dt-bindings: gpio: pca953x: document the nxp,pca6416
gpio: pca953x: add pcal6416 to the of_device_id table
gpio: gpio-omap: Remove conditional pm_runtime handling for GPIO interrupts
gpio: gpio-omap: configure edge detection for level IRQs for idle wakeup
tracing: stop making gpio tracing configurable
gpio: pca953x: Configure wake-up path when wake-up is enabled
gpio: of: Optimize quirk checks
gpio: mmio: Drop bgpio_dir_inverted
...
|
|
systemtap folks reported the following splat recently:
[ 7790.862212] WARNING: CPU: 3 PID: 26759 at arch/x86/kernel/kprobes/core.c:1022 kprobe_fault_handler+0xec/0xf0
[...]
[ 7790.864113] CPU: 3 PID: 26759 Comm: sshd Not tainted 5.1.0-0.rc7.git1.1.fc31.x86_64 #1
[ 7790.864198] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS[...]
[ 7790.864314] RIP: 0010:kprobe_fault_handler+0xec/0xf0
[ 7790.864375] Code: 48 8b 50 [...]
[ 7790.864714] RSP: 0018:ffffc06800bdbb48 EFLAGS: 00010082
[ 7790.864812] RAX: ffff9e2b75a16320 RBX: 0000000000000000 RCX: 0000000000000000
[ 7790.865306] RDX: ffffffffffffffff RSI: 000000000000000e RDI: ffffc06800bdbbf8
[ 7790.865514] RBP: ffffc06800bdbbf8 R08: 0000000000000000 R09: 0000000000000000
[ 7790.865960] R10: 0000000000000000 R11: 0000000000000000 R12: ffffc06800bdbbf8
[ 7790.866037] R13: ffff9e2ab56a0418 R14: ffff9e2b6d0bb400 R15: ffff9e2b6d268000
[ 7790.866114] FS: 00007fde49937d80(0000) GS:ffff9e2b75a00000(0000) knlGS:0000000000000000
[ 7790.866193] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7790.866318] CR2: 0000000000000000 CR3: 000000012f312000 CR4: 00000000000006e0
[ 7790.866419] Call Trace:
[ 7790.866677] do_user_addr_fault+0x64/0x480
[ 7790.867513] do_page_fault+0x33/0x210
[ 7790.868002] async_page_fault+0x1e/0x30
[ 7790.868071] RIP: 0010: (null)
[ 7790.868144] Code: Bad RIP value.
[ 7790.868229] RSP: 0018:ffffc06800bdbca8 EFLAGS: 00010282
[ 7790.868362] RAX: ffff9e2b598b60f8 RBX: ffffc06800bdbe48 RCX: 0000000000000004
[ 7790.868629] RDX: 0000000000000004 RSI: ffffc06800bdbc6c RDI: ffff9e2b598b60f0
[ 7790.868834] RBP: ffffc06800bdbcf8 R08: 0000000000000000 R09: 0000000000000004
[ 7790.870432] R10: 00000000ff6f7a03 R11: 0000000000000000 R12: 0000000000000001
[ 7790.871859] R13: ffffc06800bdbcb8 R14: 0000000000000000 R15: ffff9e2acd0a5310
[ 7790.873455] ? vfs_read+0x5/0x170
[ 7790.874639] ? vfs_read+0x1/0x170
[ 7790.875834] ? trace_call_bpf+0xf6/0x260
[ 7790.877044] ? vfs_read+0x1/0x170
[ 7790.878208] ? vfs_read+0x5/0x170
[ 7790.879345] ? kprobe_perf_func+0x233/0x260
[ 7790.880503] ? vfs_read+0x1/0x170
[ 7790.881632] ? vfs_read+0x5/0x170
[ 7790.882751] ? kprobe_ftrace_handler+0x92/0xf0
[ 7790.883926] ? __vfs_read+0x30/0x30
[ 7790.885050] ? ftrace_ops_assist_func+0x94/0x100
[ 7790.886183] ? vfs_read+0x1/0x170
[ 7790.887283] ? vfs_read+0x5/0x170
[ 7790.888348] ? ksys_read+0x5a/0xe0
[ 7790.889389] ? do_syscall_64+0x5c/0xa0
[ 7790.890401] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
After some debugging, turns out that the logic in 2cbd95a5c4fb
("bpf: change parameters of call/branch offset adjustment") has
a bug that is exposed after 52875a04f4b2 ("bpf: verifier: remove
dead code") in that we miss some of the jump offset adjustments
after code patching when we remove dead code, more concretely,
upon backward jump spanning over the area that is being removed.
BPF insns of a case that was hit pre 52875a04f4b2:
[...]
676: (85) call bpf_perf_event_output#-47616
677: (05) goto pc-636
678: (62) *(u32 *)(r10 -64) = 0
679: (bf) r7 = r10
680: (07) r7 += -64
681: (05) goto pc-44
682: (05) goto pc-1
683: (05) goto pc-1
BPF insns afterwards:
[...]
618: (85) call bpf_perf_event_output#-47616
619: (05) goto pc-638
620: (62) *(u32 *)(r10 -64) = 0
621: (bf) r7 = r10
622: (07) r7 += -64
623: (05) goto pc-44
To illustrate the bug, situation looks as follows:
____
0 | | <-- foo: [...]
1 |____|
2 |____| <-- pos / end_new ^
3 | | |
4 | | | len
5 |____| | (remove region)
6 | | <-- end_old v
7 | |
8 | | <-- curr (jmp foo)
9 |____|
The condition curr >= end_new && curr + off + 1 < end_new in the
branch delta adjustments is never hit because curr + off + 1 <
end_new is compared as unsigned and therefore curr + off + 1 >
end_new in unsigned realm as curr + off + 1 becomes negative
since the insns are memmove()'d before the offset adjustments.
Correct BPF insns after this fix:
[...]
618: (85) call bpf_perf_event_output#-47216
619: (05) goto pc-578
620: (62) *(u32 *)(r10 -64) = 0
621: (bf) r7 = r10
622: (07) r7 += -64
623: (05) goto pc-44
Note that unprivileged case is not affected from this.
Fixes: 52875a04f4b2 ("bpf: verifier: remove dead code")
Fixes: 2cbd95a5c4fb ("bpf: change parameters of call/branch offset adjustment")
Reported-by: Frank Ch. Eigler <fche@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The only purpose of klp_check_compiler_support() is to make sure that we
are not using ftrace on x86 via mcount (because that's executed only after
prologue has already happened, and that's too late for livepatching
purposes).
Now that mcount is not supported by ftrace any more, there is no need for
klp_check_compiler_support() either.
Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1905102346100.17054@cbobk.fhfr.pm
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Avoid calling cgroup_threadgroup_change_end() without having called
cgroup_threadgroup_change_begin() first.
During process creation we need to check whether the cgroup we are in
allows us to fork. To perform this check the cgroup needs to guard itself
against threadgroup changes and takes a lock.
Prior to CLONE_PIDFD the cleanup target "bad_fork_free_pid" would also need
to call cgroup_threadgroup_change_end() because said lock had already been
taken.
However, this is not the case anymore with the addition of CLONE_PIDFD. We
are now allocating a pidfd before we check whether the cgroup we're in can
fork and thus prior to taking the lock. So when copy_process() fails at the
right step it would release a lock we haven't taken.
This bug is not even very subtle to be honest. It's just not very clear
from the naming of cgroup_threadgroup_change_{begin,end}() that a lock is
taken.
Here's the relevant splat:
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fec849
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90
90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90
90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000ffed5a8c EFLAGS: 00000246 ORIG_RAX: 0000000000000078
RAX: ffffffffffffffda RBX: 0000000000003ffc RCX: 0000000000000000
RDX: 00000000200005c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000012 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(depth <= 0)
WARNING: CPU: 1 PID: 7744 at kernel/locking/lockdep.c:4052 __lock_release
kernel/locking/lockdep.c:4052 [inline]
WARNING: CPU: 1 PID: 7744 at kernel/locking/lockdep.c:4052
lock_release+0x667/0xa00 kernel/locking/lockdep.c:4321
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 7744 Comm: syz-executor007 Not tainted 5.1.0+ #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
panic+0x2cb/0x65c kernel/panic.c:214
__warn.cold+0x20/0x45 kernel/panic.c:566
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:972
RIP: 0010:__lock_release kernel/locking/lockdep.c:4052 [inline]
RIP: 0010:lock_release+0x667/0xa00 kernel/locking/lockdep.c:4321
Code: 0f 85 a0 03 00 00 8b 35 77 66 08 08 85 f6 75 23 48 c7 c6 a0 55 6b 87
48 c7 c7 40 25 6b 87 4c 89 85 70 ff ff ff e8 b7 a9 eb ff <0f> 0b 4c 8b 85
70 ff ff ff 4c 89 ea 4c 89 e6 4c 89 c7 e8 52 63 ff
RSP: 0018:ffff888094117b48 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 1ffff11012822f6f RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815af236 RDI: ffffed1012822f5b
RBP: ffff888094117c00 R08: ffff888092bfc400 R09: fffffbfff113301d
R10: fffffbfff113301c R11: ffffffff889980e3 R12: ffffffff8a451df8
R13: ffffffff8142e71f R14: ffffffff8a44cc80 R15: ffff888094117bd8
percpu_up_read.constprop.0+0xcb/0x110 include/linux/percpu-rwsem.h:92
cgroup_threadgroup_change_end include/linux/cgroup-defs.h:712 [inline]
copy_process.part.0+0x47ff/0x6710 kernel/fork.c:2222
copy_process kernel/fork.c:1772 [inline]
_do_fork+0x25d/0xfd0 kernel/fork.c:2338
__do_compat_sys_x86_clone arch/x86/ia32/sys_ia32.c:240 [inline]
__se_compat_sys_x86_clone arch/x86/ia32/sys_ia32.c:236 [inline]
__ia32_compat_sys_x86_clone+0xbc/0x140 arch/x86/ia32/sys_ia32.c:236
do_syscall_32_irqs_on arch/x86/entry/common.c:334 [inline]
do_fast_syscall_32+0x281/0xd54 arch/x86/entry/common.c:405
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fec849
Code: 85 d2 74 02 89 0a 5b 5d c3 8b |