To clear a user buffer we cannot simply use memset, we have to use
clear_user(). With a virtio-mem device that registers a vmcore_cb and
has some logically unplugged memory inside an added Linux memory block,
I can easily trigger a BUG by copying the vmcore via "cp":
systemd[1]: Starting Kdump Vmcore Save Service...
kdump[420]: Kdump is using the default log level(3).
kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/
kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/
kdump[465]: saving vmcore-dmesg.txt complete
kdump[467]: saving vmcore
BUG: unable to handle page fault for address: 00007f2374e01000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867
Oops: 0003 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014
RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86
Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 <49> c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81
RSP: 0018:ffffc9000073be08 EFLAGS: 00010212
RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000
RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008
RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50
R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000
R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8
FS: 00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0
Call Trace:
read_vmcore+0x236/0x2c0
proc_reg_read+0x55/0xa0
vfs_read+0x95/0x190
ksys_read+0x4f/0xc0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Some x86-64 CPUs have a CPU feature called "Supervisor Mode Access
Prevention (SMAP)", which is used to detect wrong access from the kernel
to user buffers like this: SMAP triggers a permissions violation on
wrong access. In the x86-64 variant of clear_user(), SMAP is properly
handled via clac()+stac().
To fix, properly use clear_user() when we're dealing with a user buffer.
Link: https://lkml.kernel.org/r/20211112092750.6921-1-david@redhat.com
Fixes: 997c136f51 ("fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge more updates from Andrew Morton:
"87 patches.
Subsystems affected by this patch series: mm (pagecache and hugetlb),
procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs,
init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork,
sysvfs, kcov, gdb, resource, selftests, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits)
ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL
ipc: check checkpoint_restore_ns_capable() to modify C/R proc files
selftests/kselftest/runner/run_one(): allow running non-executable files
virtio-mem: disallow mapping virtio-mem memory via /dev/mem
kernel/resource: disallow access to exclusive system RAM regions
kernel/resource: clean up and optimize iomem_is_exclusive()
scripts/gdb: handle split debug for vmlinux
kcov: replace local_irq_save() with a local_lock_t
kcov: avoid enable+disable interrupts if !in_task()
kcov: allocate per-CPU memory on the relevant node
Documentation/kcov: define `ip' in the example
Documentation/kcov: include types.h in the example
sysv: use BUILD_BUG_ON instead of runtime check
kernel/fork.c: unshare(): use swap() to make code cleaner
seq_file: fix passing wrong private data
seq_file: move seq_escape() to a header
signal: remove duplicate include in signal.h
crash_dump: remove duplicate include in crash_dump.h
crash_dump: fix boolreturn.cocci warning
hfs/hfsplus: use WARN_ON for sanity check
...
Problem Description:
When running running ~128 parallel instances of
TZ=/etc/localtime ps -fe >/dev/null
on a 128CPU machine, the %sys utilization reaches 97%, and perf shows
the following code path as being responsible for heavy contention on the
d_lockref spinlock:
walk_component()
lookup_fast()
d_revalidate()
pid_revalidate() // returns -ECHILD
unlazy_child()
lockref_get_not_dead(&nd->path.dentry->d_lockref) <-- contention
The reason is that pid_revalidate() is triggering a drop from RCU to ref
path walk mode. All concurrent path lookups thus try to grab a
reference to the dentry for /proc/, before re-executing pid_revalidate()
and then stepping into the /proc/$pid directory. Thus there is huge
spinlock contention.
This patch allows pid_revalidate() to execute in RCU mode, meaning that
the path lookup can successfully enter the /proc/$pid directory while
still in RCU mode. Later on, the path lookup may still drop into ref
mode, but the contention will be much reduced at this point.
By applying this patch, %sys utilization falls to around 85% under the
same workload, and the number of ps processes executed per unit time
increases by 3x-4x. Although this particular workload is a bit
contrived, we have seen some large collections of eager monitoring
scripts which produced similarly high %sys time due to contention in the
/proc directory.
As a result this patch, Al noted that several procfs methods which were
only called in ref-walk mode could now be called from RCU mode. To
ensure that this patch is safe, I audited all the inode get_link and
permission() implementations, as well as dentry d_revalidate()
implementations, in fs/proc. The purpose here is to ensure that they
either are safe to call in RCU (i.e. don't sleep) or correctly bail out
of RCU mode if they don't support it. My analysis shows that all
at-risk procfs methods are safe to call under RCU, and thus this patch
is safe.
Procfs RCU-walk Analysis:
This analysis is up-to-date with 5.15-rc3. When called under RCU mode,
these functions have arguments as follows:
* get_link() receives a NULL dentry pointer when called in RCU mode.
* permission() receives MAY_NOT_BLOCK in the mode parameter when called
from RCU.
* d_revalidate() receives LOOKUP_RCU in flags.
For the following functions, either they are trivially RCU safe, or they
explicitly bail at the beginning of the function when they run:
proc_ns_get_link (bails out)
proc_get_link (RCU safe)
proc_pid_get_link (bails out)
map_files_d_revalidate (bails out)
map_misc_d_revalidate (bails out)
proc_net_d_revalidate (RCU safe)
proc_sys_revalidate (bails out, also not under /proc/$pid)
tid_fd_revalidate (bails out)
proc_sys_permission (not under /proc/$pid)
The remainder of the functions require a bit more detail:
* proc_fd_permission: RCU safe. All of the body of this function is
under rcu_read_lock(), except generic_permission() which declares
itself RCU safe in its documentation string.
* proc_self_get_link uses GFP_ATOMIC in the RCU case, so it is RCU aware
and otherwise looks safe. The same is true of proc_thread_self_get_link.
* proc_map_files_get_link: calls ns_capable, which calls capable(), and
thus calls into the audit code (see note #1 below). The remainder is
just a call to the trivially safe proc_pid_get_link().
* proc_pid_permission: calls ptrace_may_access(), which appears RCU
safe, although it does call into the "security_ptrace_access_check()"
hook, which looks safe under smack and selinux. Just the audit code is
of concern. Also uses get_task_struct() and put_task_struct(), see
note #2 below.
* proc_tid_comm_permission: Appears safe, though calls put_task_struct
(see note #2 below).
Note #1:
Most of the concern of RCU safety has centered around the audit code.
However, since b17ec22fb3 ("selinux: slow_avc_audit has become
non-blocking"), it's safe to call this code under RCU. So all of the
above are safe by my estimation.
Note #2: get_task_struct() and put_task_struct():
The majority of get_task_struct() is under RCU read lock, and in any
case it is a simple increment. But put_task_struct() is complex, given
that it could at some point free the task struct, and this process has
many steps which I couldn't manually verify. However, several other
places call put_task_struct() under RCU, so it appears safe to use
here too (see kernel/hung_task.c:165 or rcu/tree-stall.h:296)
Patch description:
pid_revalidate() drops from RCU into REF lookup mode. When many threads
are resolving paths within /proc in parallel, this can result in heavy
spinlock contention on d_lockref as each thread tries to grab a
reference to the /proc dentry (and drop it shortly thereafter).
Investigation indicates that it is not necessary to drop RCU in
pid_revalidate(), as no RCU data is modified and the function never
sleeps. So, remove the LOOKUP_RCU check.
Link: https://lkml.kernel.org/r/20211004175629.292270-2-stephen.s.brennan@oracle.com
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's support multiple registered callbacks, making sure that
registering vmcore callbacks cannot fail. Make the callback return a
bool instead of an int, handling how to deal with errors internally.
Drop unused HAVE_OLDMEM_PFN_IS_RAM.
We soon want to make use of this infrastructure from other drivers:
virtio-mem, registering one callback for each virtio-mem device, to
prevent reading unplugged virtio-mem memory.
Handle it via a generic vmcore_cb structure, prepared for future
extensions: for example, once we support virtio-mem on s390x where the
vmcore is completely constructed in the second kernel, we want to detect
and add plugged virtio-mem memory ranges to the vmcore in order for them
to get dumped properly.
Handle corner cases that are unexpected and shouldn't happen in sane
setups: registering a callback after the vmcore has already been opened
(warn only) and unregistering a callback after the vmcore has already been
opened (warn and essentially read only zeroes from that point on).
Link: https://lkml.kernel.org/r/20211005121430.30136-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
Firstly, check_shmem_swap variable is actually not necessary, because
it's always set with pte_hole hook; checking each would work.
Meanwhile, the check within smaps_pte_entry is not easy to follow.
E.g., pte_none() check is not needed as "!pte_present && !is_swap_pte"
is the same. Since at it, use the pte_hole() helper rather than dup the
page cache lookup.
Still keep the CONFIG_SHMEM part so the code can be optimized to nop for
!SHMEM.
There will be a very slight functional change in smaps_pte_entry(), that
for !SHMEM we'll return early for pte_none (before checking page==NULL),
but that's even nicer.
Link: https://lkml.kernel.org/r/20210917164756.8586-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/smaps: Fixes and optimizations on shmem swap handling".
This patch (of 3):
The shmem swap calculation on the privately writable mappings are using
wrong parameters as spotted by Vlastimil. Fix them. This was
introduced in commit 48131e03ca ("mm, proc: reduce cost of
/proc/pid/smaps for unpopulated shmem mappings"), when shmem_swap_usage
was reworked to shmem_partial_swap_usage.
Test program:
void main(void)
{
char *buffer, *p;
int i, fd;
fd = memfd_create("test", 0);
assert(fd > 0);
/* isize==2M*3, fill in pages, swap them out */
ftruncate(fd, SIZE_2M * 3);
buffer = mmap(NULL, SIZE_2M * 3, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
assert(buffer);
for (i = 0, p = buffer; i < SIZE_2M * 3 / 4096; i++) {
*p = 1;
p += 4096;
}
madvise(buffer, SIZE_2M * 3, MADV_PAGEOUT);
munmap(buffer, SIZE_2M * 3);
/*
* Remap with private+writtable mappings on partial of the inode (<= 2M*3),
* while the size must also be >= 2M*2 to make sure there's a none pmd so
* smaps_pte_hole will be triggered.
*/
buffer = mmap(NULL, SIZE_2M * 2, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
printf("pid=%d, buffer=%p\n", getpid(), buffer);
/* Check /proc/$PID/smap_rollup, should see 4MB swap */
sleep(1000000);
}
Before the patch, smaps_rollup shows <4MB swap and the number will be
random depending on the alignment of the buffer of mmap() allocated.
After this patch, it'll show 4MB.
Link: https://lkml.kernel.org/r/20210917164756.8586-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20210917164756.8586-2-peterx@redhat.com
Fixes: 48131e03ca ("mm, proc: reduce cost of /proc/pid/smaps for unpopulated shmem mappings")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull per signal_struct coredumps from Eric Biederman:
"Current coredumps are mixed up with the exit code, the signal handling
code, and the ptrace code making coredumps much more complicated than
necessary and difficult to follow.
This series of changes starts with ptrace_stop and cleans it up,
making it easier to follow what is happening in ptrace_stop. Then
cleans up the exec interactions with coredumps. Then cleans up the
coredump interactions with exit. Finally the coredump interactions
with the signal handling code is cleaned up.
The first and last changes are bug fixes for minor bugs.
I believe the fact that vfork followed by execve can kill the process
the called vfork if exec fails is sufficient justification to change
the userspace visible behavior.
In previous discussions some of these changes were organized
differently and individually appeared to make the code base worse. As
currently written I believe they all stand on their own as cleanups
and bug fixes.
Which means that even if the worst should happen and the last change
needs to be reverted for some unimaginable reason, the code base will
still be improved.
If the worst does not happen there are a more cleanups that can be
made. Signals that generate coredumps can easily become eligible for
short circuit delivery in complete_signal. The entire rendezvous for
generating a coredump can move into get_signal. The function
force_sig_info_to_task be written in a way that does not modify the
signal handling state of the target task (because coredumps are
eligible for short circuit delivery). Many of these future cleanups
can be done another way but nothing so cleanly as if coredumps become
per signal_struct"
* 'per_signal_struct_coredumps-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
coredump: Limit coredumps to a single thread group
coredump: Don't perform any cleanups before dumping core
exit: Factor coredump_exit_mm out of exit_mm
exec: Check for a pending fatal signal instead of core_state
ptrace: Remove the unnecessary arguments from arch_ptrace_stop
signal: Remove the bogus sigkill_pending in ptrace_stop
Pull generic confidential computing updates from Borislav Petkov:
"Add an interface called cc_platform_has() which is supposed to be used
by confidential computing solutions to query different aspects of the
system.
The intent behind it is to unify testing of such aspects instead of
having each confidential computing solution add its own set of tests
to code paths in the kernel, leading to an unwieldy mess"
* tag 'x86_cc_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
treewide: Replace the use of mem_encrypt_active() with cc_platform_has()
x86/sev: Replace occurrences of sev_es_active() with cc_platform_has()
x86/sev: Replace occurrences of sev_active() with cc_platform_has()
x86/sme: Replace occurrences of sme_active() with cc_platform_has()
powerpc/pseries/svm: Add a powerpc version of cc_platform_has()
x86/sev: Add an x86 version of cc_platform_has()
arch/cc: Introduce a function to check for confidential computing features
x86/ioremap: Selectively build arch override encryption functions
The implementations of get_wchan() can be expensive. The only information
imparted here is whether or not a process is currently blocked in the
scheduler (and even this doesn't need to be exact). Avoid doing the
heavy lifting of stack walking and just report that information by using
task_is_running().
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211008111626.211281780@infradead.org
Today when a signal is delivered with a handler of SIG_DFL whose
default behavior is to generate a core dump not only that process but
every process that shares the mm is killed.
In the case of vfork this looks like a real world problem. Consider
the following well defined sequence.
if (vfork() == 0) {
execve(...);
_exit(EXIT_FAILURE);
}
If a signal that generates a core dump is received after vfork but
before the execve changes the mm the process that called vfork will
also be killed (as the mm is shared).
Similarly if the execve fails after the point of no return the kernel
delivers SIGSEGV which will kill both the exec'ing process and because
the mm is shared the process that called vfork as well.
As far as I can tell this behavior is a violation of people's
reasonable expectations, POSIX, and is unnecessarily fragile when the
system is low on memory.
Solve this by making a userspace visible change to only kill a single
process/thread group. This is possible because Jann Horn recently
modified[1] the coredump code so that the mm can safely be modified
while the coredump is happening. With LinuxThreads long gone I don't
expect anyone to have a notice this behavior change in practice.
To accomplish this move the core_state pointer from mm_struct to
signal_struct, which allows different thread groups to coredump
simultatenously.
In zap_threads remove the work to kill anything except for the current
thread group.
v2: Remove core_state from the VM_BUG_ON_MM print to fix
compile failure when CONFIG_DEBUG_VM is enabled.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
[1] a07279c9a8 ("binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot")
Fixes: d89f3847def4 ("[PATCH] thread-aware coredumps, 2.5.43-C3")
History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Link: https://lkml.kernel.org/r/87y27mvnke.fsf@disp2133
Link: https://lkml.kernel.org/r/20211007144701.67592574@canb.auug.org.au
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
/proc/uptime reports idle time by reading the CPUTIME_IDLE field from
the per-cpu kcpustats. However, on NO_HZ systems, idle time is not
continually updated on idle cpus, leading this value to appear
incorrectly small.
/proc/stat performs an accounting update when reading idle time; we
can use the same approach for uptime.
With this patch, /proc/stat and /proc/uptime now agree on idle time.
Additionally, the following shows idle time tick up consistently on an
idle machine:
(while true; do cat /proc/uptime; sleep 1; done) | awk '{print $2-prev; prev=$2}'
Reported-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lkml.kernel.org/r/20210827165438.3280779-1-joshdon@google.com
Replace uses of mem_encrypt_active() with calls to cc_platform_has() with
the CC_ATTR_MEM_ENCRYPT attribute.
Remove the implementation of mem_encrypt_active() across all arches.
For s390, since the default implementation of the cc_platform_has()
matches the s390 implementation of mem_encrypt_active(), cc_platform_has()
does not need to be implemented in s390 (the config option
ARCH_HAS_CC_PLATFORM is not set).
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-9-bp@alien8.de
Merge more updates from Andrew Morton:
"147 patches, based on 7d2a07b769.
Subsystems affected by this patch series: mm (memory-hotplug, rmap,
ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan),
alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib,
checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig,
selftests, ipc, and scripts"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
scripts: check_extable: fix typo in user error message
mm/workingset: correct kernel-doc notations
ipc: replace costly bailout check in sysvipc_find_ipc()
selftests/memfd: remove unused variable
Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
configs: remove the obsolete CONFIG_INPUT_POLLDEV
prctl: allow to setup brk for et_dyn executables
pid: cleanup the stale comment mentioning pidmap_init().
kernel/fork.c: unexport get_{mm,task}_exe_file
coredump: fix memleak in dump_vma_snapshot()
fs/coredump.c: log if a core dump is aborted due to changed file permissions
nilfs2: use refcount_dec_and_lock() to fix potential UAF
nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
nilfs2: fix NULL pointer in nilfs_##name##_attr_release
nilfs2: fix memory leak in nilfs_sysfs_create_device_group
trap: cleanup trap_init()
init: move usermodehelper_enable() to populate_rootfs()
...
All in-tree users of MAP_DENYWRITE are gone. MAP_DENYWRITE cannot be
set from user space, so all users are gone; let's remove it.
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Pull vfs name lookup updates from Al Viro:
"Small namei.c patch series, mostly to simplify the rules for nameidata
state. It's actually from the previous cycle - but I didn't post it
for review in time...
Changes visible outside of fs/namei.c: file_open_root() calling
conventions change, some freed bits in LOOKUP_... space"
* 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
namei: make sure nd->depth is always valid
teach set_nameidata() to handle setting the root as well
take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space
switch file_open_root() to struct path
Pull tracing updates from Steven Rostedt:
- Added option for per CPU threads to the hwlat tracer
- Have hwlat tracer handle hotplug CPUs
- New tracer: osnoise, that detects latency caused by interrupts,
softirqs and scheduling of other tasks.
- Added timerlat tracer that creates a thread and measures in detail
what sources of latency it has for wake ups.
- Removed the "success" field of the sched_wakeup trace event. This has
been hardcoded as "1" since 2015, no tooling should be looking at it
now. If one exists, we can revert this commit, fix that tool and try
to remove it again in the future.
- tgid mapping fixed to handle more than PID_MAX_DEFAULT pids/tgids.
- New boot command line option "tp_printk_stop", as tp_printk causes
trace events to write to console. When user space starts, this can
easily live lock the system. Having a boot option to stop just after
boot up is useful to prevent that from happening.
- Have ftrace_dump_on_oops boot command line option take numbers that
match the numbers shown in /proc/sys/kernel/ftrace_dump_on_oops.
- Bootconfig clean ups, fixes and enhancements.
- New ktest script that tests bootconfig options.
- Add tracepoint_probe_register_may_exist() to register a tracepoint
without triggering a WARN*() if it already exists. BPF has a path
from user space that can do this. All other paths are considered a
bug.
- Small clean ups and fixes
* tag 'trace-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (49 commits)
tracing: Resize tgid_map to pid_max, not PID_MAX_DEFAULT
tracing: Simplify & fix saved_tgids logic
treewide: Add missing semicolons to __assign_str uses
tracing: Change variable type as bool for clean-up
trace/timerlat: Fix indentation on timerlat_main()
trace/osnoise: Make 'noise' variable s64 in run_osnoise()
tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing
tracing: Fix spelling in osnoise tracer "interferences" -> "interference"
Documentation: Fix a typo on trace/osnoise-tracer
trace/osnoise: Fix return value on osnoise_init_hotplug_support
trace/osnoise: Make interval u64 on osnoise_main
trace/osnoise: Fix 'no previous prototype' warnings
tracing: Have osnoise_main() add a quiescent state for task rcu
seq_buf: Make trace_seq_putmem_hex() support data longer than 8
seq_buf: Fix overflow in seq_buf_putmem_hex()
trace/osnoise: Support hotplug operations
trace/hwlat: Support hotplug operations
trace/hwlat: Protect kdata->kthread with get/put_online_cpus
trace: Add timerlat tracer
trace: Add osnoise tracer
...
Merge more updates from Andrew Morton:
"190 patches.
Subsystems affected by this patch series: mm (hugetlb, userfaultfd,
vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock,
migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap,
zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc,
core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs,
signals, exec, kcov, selftests, compress/decompress, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits)
ipc/util.c: use binary search for max_idx
ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock
ipc: use kmalloc for msg_queue and shmid_kernel
ipc sem: use kvmalloc for sem_undo allocation
lib/decompressors: remove set but not used variabled 'level'
selftests/vm/pkeys: exercise x86 XSAVE init state
selftests/vm/pkeys: refill shadow register after implicit kernel write
selftests/vm/pkeys: handle negative sys_pkey_alloc() return code
selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random
kcov: add __no_sanitize_coverage to fix noinstr for all architectures
exec: remove checks in __register_bimfmt()
x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
hfsplus: report create_date to kstat.btime
hfsplus: remove unnecessary oom message
nilfs2: remove redundant continue statement in a while-loop
kprobes: remove duplicated strong free_insn_page in x86 and s390
init: print out unknown kernel parameters
checkpatch: do not complain about positive return values starting with EPOLL
checkpatch: improve the indented label test
checkpatch: scripts/spdxcheck.py now requires python3
...
Android captures per-process system memory state when certain low memory
events (e.g a foreground app kill) occur, to identify potential memory
hoggers. In order to measure how much memory a process actually consumes,
it is necessary to include the DMA buffer sizes for that process in the
memory accounting. Since the handle to DMA buffers are raw FDs, it is
important to be able to identify which processes have FD references to a
DMA buffer.
Currently, DMA buffer FDs can be accounted using /proc/<pid>/fd/* and
/proc/<pid>/fdinfo -- both are only readable by the process owner, as
follows:
1. Do a readlink on each FD.
2. If the target path begins with "/dmabuf", then the FD is a dmabuf FD.
3. stat the file to get the dmabuf inode number.
4. Read/ proc/<pid>/fdinfo/<fd>, to get the DMA buffer size.
Accessing other processes' fdinfo requires root privileges. This limits
the use of the interface to debugging environments and is not suitable for
production builds. Granting root privileges even to a system process
increases the attack surface and is highly undesirable.
Since fdinfo doesn't permit reading process memory and manipulating
process state, allow accessing fdinfo under PTRACE_MODE_READ_FSCRED.
Link: https://lkml.kernel.org/r/20210308170651.919148-1-kaleshsingh@google.com
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Suggested-by: Jann Horn <jannh@google.com>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alexey Gladkov <gladkov.alexey@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: James Morris <jamorris@linux.microsoft.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
