Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
set_mask_bits and bit_clear_unless. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg (and
related move instruction in front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails, enabling further code simplifications.
Link: https://lkml.kernel.org/r/20220822143851.3290-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
Two main problems with kmap(): (1) It comes with an overhead as mapping
space is restricted and protected by a global lock for synchronization and
(2) it also requires global TLB invalidation when the kmap's pool wraps
and it might block when the mapping space is fully utilized until a slot
becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.
Since its use in btree.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in btree.c. Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220821180400.8198-4-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
Two main problems with kmap(): (1) It comes with an overhead as mapping
space is restricted and protected by a global lock for synchronization and
(2) it also requires global TLB invalidation when the kmap's pool wraps
and it might block when the mapping space is fully utilized until a slot
becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.
Since its use in bnode.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in bnode.c. Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220821180400.8198-3-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "hfs: Replace kmap() with kmap_local_page()".
kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmaps pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.
Since its use in fs/hfs is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in fs/hfs. Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().
Fix a bug due to a page being not unmapped if the code jumps to the
"fail_page" label (1/3).
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
This patch (of 3):
Several paths within hfs_btree_open() jump to the "fail_page" label where
put_page() is called while the page is still mapped.
Call kunmap() to unmap the page soon before put_page().
Link: https://lkml.kernel.org/r/20220821180400.8198-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20220821180400.8198-2-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Matthew Wilcox <willy@infradead.org>]
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.
Since its use in kexec_core.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in kexec_core.c.
Tested on a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220821182519.9483-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old
in __get_reqs_available. x86 CMPXCHG instruction returns success in ZF
flag, so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).
Also, atomic_try_cmpxchg implicitly assigns old *ptr value to "old" when
cmpxchg fails, enabling further code simplifications.
No functional change intended.
Link: https://lkml.kernel.org/r/20220714164851.3055-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
discard_buffer. x86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg (and related move instruction in
front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails, enabling further code simplifications.
Note that the value from *ptr should be read using READ_ONCE to prevent
the compiler from merging, refetching or reordering the read.
No functional change intended.
Link: https://lkml.kernel.org/r/20220714171653.12128-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
clock_gettime(CLOCK_MONOTONIC, &tp) is very precise on ia64 as it uses ITC
(similar to rdtsc on x86). It's not quite a hrtimer as it is a few times
slower than 1ns. Usually 2-3ns.
clock_getres(CLOCK_MONOTONIC, &res) never reflected that fact and reported
0.04s precision (1/HZ value).
In https://bugs.gentoo.org/596382 gstreamer's test suite failed loudly
when it noticed precision discrepancy.
Before the change:
clock_getres(CLOCK_MONOTONIC, &res) reported 250Hz precision.
After the change:
clock_getres(CLOCK_MONOTONIC, &res) reports ITC (400Mhz) precision.
The patch is based on matoro's fix. I added a bit of explanation why we
need to special-case arch-specific clock_getres().
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20220820181813.2275195-1-slyich@gmail.com
Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
Cc: matoro <matoro_mailinglist_kernel@matoro.tk>
Cc: Émeric Maschino <emeric.maschino@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
llist_add_batch and llist_del_first. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg.
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails, enabling further code simplifications.
No functional change intended.
Link: https://lkml.kernel.org/r/20220712144917.4497-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Attempting to get a crash dump out of a debug PREEMPT_RT kernel via an NMI
panic() doesn't work. The cause of that lies in the PREEMPT_RT definition
of mutex_trylock():
if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
return 0;
This prevents an nmi_panic() from executing the main body of
__crash_kexec() which does the actual kexec into the kdump kernel. The
warning and return are explained by:
6ce47fd961 ("rtmutex: Warn if trylock is called from hard/softirq context")
[...]
The reasons for this are:
1) There is a potential deadlock in the slowpath
2) Another cpu which blocks on the rtmutex will boost the task
which allegedly locked the rtmutex, but that cannot work
because the hard/softirq context borrows the task context.
Furthermore, grabbing the lock isn't NMI safe, so do away with kexec_mutex
and replace it with an atomic variable. This is somewhat overzealous as
*some* callsites could keep using a mutex (e.g. the sysfs-facing ones
like crash_shrink_memory()), but this has the benefit of involving a
single unified lock and preventing any future NMI-related surprises.
Tested by triggering NMI panics via:
$ echo 1 > /proc/sys/kernel/panic_on_unrecovered_nmi
$ echo 1 > /proc/sys/kernel/unknown_nmi_panic
$ echo 1 > /proc/sys/kernel/panic
$ ipmitool power diag
Link: https://lkml.kernel.org/r/20220630223258.4144112-3-vschneid@redhat.com
Fixes: 6ce47fd961 ("rtmutex: Warn if trylock is called from hard/softirq context")
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "kexec, panic: Making crash_kexec() NMI safe", v4.
This patch (of 2):
Most acquistions of kexec_mutex are done via mutex_trylock() - those were
a direct "translation" from:
8c5a1cf0ad ("kexec: use a mutex for locking rather than xchg()")
there have however been two additions since then that use mutex_lock():
crash_get_memory_size() and crash_shrink_memory().
A later commit will replace said mutex with an atomic variable, and
locking operations will become atomic_cmpxchg(). Rather than having those
mutex_lock() become while (atomic_cmpxchg(&lock, 0, 1)), turn them into
trylocks that can return -EBUSY on acquisition failure.
This does halve the printable size of the crash kernel, but that's still
neighbouring 2G for 32bit kernels which should be ample enough.
Link: https://lkml.kernel.org/r/20220630223258.4144112-1-vschneid@redhat.com
Link: https://lkml.kernel.org/r/20220630223258.4144112-2-vschneid@redhat.com
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() and kmap_atomic() are being deprecated in favor of
kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
kmap_local_page() is safe from any context and is therefore redundant with
kmap_atomic() with the exception of any pagefault or preemption disable
requirements. However, using kmap_atomic() for these side effects makes
the code less clear. So any requirement for pagefault or preemption
disable should be made explicitly.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored.
Link: https://lkml.kernel.org/r/20220813220034.806698-1-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The use of kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
Tasks can be preempted and, when scheduled to run again, the kernel
virtual addresses are restored and still valid. It is faster than kmap()
in kernels with HIGHMEM enabled.
Since kmap_local_page() can be safely used in compress.c, it should be
called everywhere instead of kmap().
Therefore, replace kmap() with kmap_local_page() in compress.c. Where it
is needed, use memzero_page() instead of open coding kmap_local_page()
plus memset() to fill the pages with zeros. Delete the redundant
flush_dcache_page() in the two call sites of memzero_page().
Tested with mkisofs on a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220801122709.8164-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Pali Rohár <pali@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are cases where the IP pointer in a Code: line in an oops doesn't
point at the beginning of an instruction:
Code: 0f bd c2 e9 a0 cd b5 e4 48 0f bd c2 e9 97 cd b5 e4 0f 1f 80 00 00 00 00 \
e9 8b cd b5 e4 0f 1f 00 66 0f a3 d0 e9 7f cd b5 e4 0f 1f <80> 00 00 00 \
00 0f a3 d0 e9 70 cd b5 e4 48 0f a3 d0 e9 67 cd b5
e9 7f cd b5 e4 jmp 0xffffffffe4b5cda8
0f 1f 80 00 00 00 00 nopl 0x0(%rax)
^^
and the current way of determining the faulting instruction line doesn't
work because disassembled instructions are counted from the IP byte to
the end and when that thing points in the middle, the trailing bytes can
be interpreted as different insns:
Code starting with the faulting instruction
===========================================
0: 80 00 00 addb $0x0,(%rax)
3: 00 00 add %al,(%rax)
whereas, this is part of
0f 1f 80 00 00 00 00 nopl 0x0(%rax)
5: 0f a3 d0 bt %edx,%eax
...
leading to:
1d: 0f 1f 00 nopl (%rax)
20: 66 0f a3 d0 bt %dx,%ax
24:* e9 7f cd b5 e4 jmp 0xffffffffe4b5cda8 <-- trapping instruction
29: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
30: 0f a3 d0 bt %edx,%eax
which is the wrong faulting instruction.
Change the way the faulting line number is determined by matching the
opcode bytes from the beginning, leading to correct output:
1d: 0f 1f 00 nopl (%rax)
20: 66 0f a3 d0 bt %dx,%ax
24: e9 7f cd b5 e4 jmp 0xffffffffe4b5cda8
29:* 0f 1f 80 00 00 00 00 nopl 0x0(%rax) <-- trapping instruction
30: 0f a3 d0 bt %edx,%eax
While at it, make decodecode use bash as the interpreter - that thing
should be present on everything by now. It simplifies the code a lot
too.
Link: https://lkml.kernel.org/r/20220808085928.29840-1-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.
Since its use in btree.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in btree.c.
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220809203105.26183-5-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.
Since its use in bitmap.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in bitmap.c.
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220809203105.26183-4-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
Two main problems with kmap(): (1) It comes with an overhead as mapping
space is restricted and protected by a global lock for synchronization and
(2) it also requires global TLB invalidation when the kmap's pool wraps
and it might block when the mapping space is fully utilized until a slot
becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.
Since its use in bnode.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in bnode.c. Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220809203105.26183-3-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "hfsplus: Replace kmap() with kmap_local_page()".
kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.
Since its use in fs/hfsplus is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in fs/hfsplus. Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().
Fix a bug due to a page being not unmapped if the code jumps to the
"fail_page" label (1/4).
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
This patch (of 4):
Several paths within hfs_btree_open() jump to the "fail_page" label where
put_page() is called while the page is still mapped.
Call kunmap() to unmap the page soon before put_page().
Link: https://lkml.kernel.org/r/20220809203105.26183-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20220809203105.26183-2-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull more hotfixes from Andrew Morton:
"Seventeen hotfixes. Mostly memory management things.
Ten patches are cc:stable, addressing pre-6.0 issues"
* tag 'mm-hotfixes-stable-2022-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
.mailmap: update Luca Ceresoli's e-mail address
mm/mprotect: only reference swap pfn page if type match
squashfs: don't call kmalloc in decompressors
mm/damon/dbgfs: avoid duplicate context directory creation
mailmap: update email address for Colin King
asm-generic: sections: refactor memory_intersects
bootmem: remove the vmemmap pages from kmemleak in put_page_bootmem
ocfs2: fix freeing uninitialized resource on ocfs2_dlm_shutdown
Revert "memcg: cleanup racy sum avoidance code"
mm/zsmalloc: do not attempt to free IS_ERR handle
binder_alloc: add missing mmap_lock calls when using the VMA
mm: re-allow pinning of zero pfns (again)
vmcoreinfo: add kallsyms_num_syms symbol
mailmap: update Guilherme G. Piccoli's email addresses
writeback: avoid use-after-free after removing device
shmem: update folio if shmem_replace_page() updates the page
mm/hugetlb: avoid corrupting page->mapping in hugetlb_mcopy_atomic_pte
Pull bitmap fixes from Yury Norov:
"Fix the reported issues, and implements the suggested improvements,
for the version of the cpumask tests [1] that was merged with commit
c41e8866c2 ("lib/test: introduce cpumask KUnit test suite").
These changes include fixes for the tests, and better alignment with
the KUnit style guidelines"
* tag 'bitmap-6.0-rc3' of github.com:/norov/linux:
lib/cpumask_kunit: add tests file to MAINTAINERS
lib/cpumask_kunit: log mask contents
lib/test_cpumask: follow KUnit style guidelines
lib/test_cpumask: fix cpu_possible_mask last test
lib/test_cpumask: drop cpu_possible_mask full test
When user tries to create a DAMON context via the DAMON debugfs interface
with a name of an already existing context, the context directory creation
fails but a new context is created and added in the internal data
structure, due to absence of the directory creation success check. As a
result, memory could leak and DAMON cannot be turned on. An example test
case is as below:
# cd /sys/kernel/debug/damon/
# echo "off" > monitor_on
# echo paddr > target_ids
# echo "abc" > mk_context
# echo "abc" > mk_context
# echo $$ > abc/target_ids
# echo "on" > monitor_on <<< fails
Return value of 'debugfs_create_dir()' is expected to be ignored in
general, but this is an exceptional case as DAMON feature is depending
on the debugfs functionality and it has the potential duplicate name
issue. This commit therefore fixes the issue by checking the directory
creation failure and immediately return the error in the case.
Link: https://lkml.kernel.org/r/20220821180853.2400-1-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: Badari Pulavarty <badari.pulavarty@intel.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [ 5.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are two problems with the current code of memory_intersects:
First, it doesn't check whether the region (begin, end) falls inside the
region (virt, vend), that is (virt < begin && vend > end).
The second problem is if vend is equal to begin, it will return true but
this is wrong since vend (virt + size) is not the last address of the
memory region but (virt + size -1) is. The wrong determination will
trigger the misreporting when the function check_for_illegal_area calls
memory_intersects to check if the dma region intersects with stext region.
The misreporting is as below (stext is at 0x80100000):
WARNING: CPU: 0 PID: 77 at kernel/dma/debug.c:1073 check_for_illegal_area+0x130/0x168
DMA-API: chipidea-usb2 e0002000.usb: device driver maps memory from kernel text or rodata [addr=800f0000] [len=65536]
Modules linked in:
CPU: 1 PID: 77 Comm: usb-storage Not tainted 5.19.0-yocto-standard #5
Hardware name: Xilinx Zynq Platform
unwind_backtrace from show_stack+0x18/0x1c
show_stack from dump_stack_lvl+0x58/0x70
dump_stack_lvl from __warn+0xb0/0x198
__warn from warn_slowpath_fmt+0x80/0xb4
warn_slowpath_fmt from check_for_illegal_area+0x130/0x168
check_for_illegal_area from debug_dma_map_sg+0x94/0x368
debug_dma_map_sg from __dma_map_sg_attrs+0x114/0x128
__dma_map_sg_attrs from dma_map_sg_attrs+0x18/0x24
dma_map_sg_attrs from usb_hcd_map_urb_for_dma+0x250/0x3b4
usb_hcd_map_urb_for_dma from usb_hcd_submit_urb+0x194/0x214
usb_hcd_submit_urb from usb_sg_wait+0xa4/0x118
usb_sg_wait from usb_stor_bulk_transfer_sglist+0xa0/0xec
usb_stor_bulk_transfer_sglist from usb_stor_bulk_srb+0x38/0x70
usb_stor_bulk_srb from usb_stor_Bulk_transport+0x150/0x360
usb_stor_Bulk_transport from usb_stor_invoke_transport+0x38/0x440
usb_stor_invoke_transport from usb_stor_control_thread+0x1e0/0x238
usb_stor_control_thread from kthread+0xf8/0x104
kthread from ret_from_fork+0x14/0x2c
Refactor memory_intersects to fix the two problems above.
Before the 1d7db834a0 ("dma-debug: use memory_intersects()
directly"), memory_intersects is called only by printk_late_init:
printk_late_init -> init_section_intersects ->memory_intersects.
There were few places where memory_intersects was called.
When commit 1d7db834a0 ("dma-debug: use memory_intersects()
directly") was merged and CONFIG_DMA_API_DEBUG is enabled, the DMA
subsystem uses it to check for an illegal area and the calltrace above
is triggered.
[akpm@linux-foundation.org: fix nearby comment typo]
Link: https://lkml.kernel.org/r/20220819081145.948016-1-quanyang.wang@windriver.com
Fixes: 9795593625 ("asm/sections: add helpers to check for section data")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thierry Reding <treding@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The vmemmap pages is marked by kmemleak when allocated from memblock.
Remove it from kmemleak when freeing the page. Otherwise, when we reuse
the page, kmemleak may report such an error and then stop working.
kmemleak: Cannot insert 0xffff98fb6eab3d40 into the object search tree (overlaps existing)
kmemleak: Kernel memory leak detector disabled
kmemleak: Object 0xffff98fb6be00000 (size 335544320):
kmemleak: comm "swapper", pid 0, jiffies 4294892296
kmemleak: min_count = 0
kmemleak: count = 0
kmemleak: flags = 0x1
kmemleak: checksum = 0
kmemleak: backtrace:
Link: https://lkml.kernel.org/r/20220819094005.2928241-1-liushixin2@huawei.com
Fixes: f41f2ed43c (mm: hugetlb: free the vmemmap pages associated with each HugeTLB page)
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 96e51ccf1a.
Recently we started running the kernel with rstat infrastructure on
production traffic and begin to see negative memcg stats values.
Particularly the 'sock' stat is the one which we observed having negative
value.
$ grep "sock " /mnt/memory/job/memory.stat
sock 253952
total_sock 18446744073708724224
Re-run after couple of seconds
$ grep "sock " /mnt/memory/job/memory.stat
sock 253952
total_sock 53248
For now we are only seeing this issue on large machines (256 CPUs) and
only with 'sock' stat. I think the networking stack increase the stat on
one cpu and decrease it on another cpu much more often. So, this negative
sock is due to rstat flusher flushing the stats on the CPU that has seen
the decrement of sock but missed the CPU that has increments. A typical
race condition.
For easy stable backport, revert is the most simple solution. For long
term solution, I am thinking of two directions. First is just reduce the
race window by optimizing the rstat flusher. Second is if the reader sees
a negative stat value, force flush and restart the stat collection.
Basically retry but limited.
Link: https://lkml.kernel.org/r/20220817172139.3141101-1-shakeelb@google.com
Fixes: 96e51ccf1a ("memcg: cleanup racy sum avoidance code")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org> [5.15]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a disk is removed, bdi_unregister gets called to stop further
writeback and wait for associated delayed work to complete. However,
wb_inode_writeback_end() may schedule bandwidth estimation dwork after
this has completed, which can result in the timer attempting to access the
just freed bdi_writeback.
Fix this by checking if the bdi_writeback is alive, similar to when
scheduling writeback work.
Since this requires wb->work_lock, and wb_inode_writeback_end() may get
called from interrupt, switch wb->work_lock to an irqsafe lock.
Link: https://lkml.kernel.org/r/20220801155034.3772543-1-khazhy@google.com
Fixes: 45a2966fd6 ("writeback: fix bandwidth estimate for spiky workload")
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
