commit c1e6311771 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 94f0b2d4a1 upstream.
Commit 591a22c14d ("proc: Track /proc/$pid/attr/ opener mm_struct") we
started using __mem_open() to track the mm_struct at open-time, so that
we could then check it for writes.
But that also ended up making the permission checks at open time much
stricter - and not just for writes, but for reads too. And that in turn
caused a regression for at least Fedora 29, where NIC interfaces fail to
start when using NetworkManager.
Since only the write side wanted the mm_struct test, ignore any failures
by __mem_open() at open time, leaving reads unaffected. The write()
time verification of the mm_struct pointer will then catch the failure
case because a NULL pointer will not match a valid 'current->mm'.
Link: https://lore.kernel.org/netdev/YMjTlp2FSJYvoyFa@unreal/
Fixes: 591a22c14d ("proc: Track /proc/$pid/attr/ opener mm_struct")
Reported-and-tested-by: Leon Romanovsky <leon@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 591a22c14d upstream.
Commit bfb819ea20 ("proc: Check /proc/$pid/attr/ writes against file opener")
tried to make sure that there could not be a confusion between the opener of
a /proc/$pid/attr/ file and the writer. It used struct cred to make sure
the privileges didn't change. However, there were existing cases where a more
privileged thread was passing the opened fd to a differently privileged thread
(during container setup). Instead, use mm_struct to track whether the opener
and writer are still the same process. (This is what several other proc files
already do, though for different reasons.)
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>
Reported-by: Andrea Righi <andrea.righi@canonical.com>
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Fixes: bfb819ea20 ("proc: Check /proc/$pid/attr/ writes against file opener")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 8d4c3e76e3 ]
If this is attempted by a kthread, then return -EOPNOTSUPP as we don't
currently support that. Once we can get task_pid_ptr() doing the right
thing, then this can go away again.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ef1548adad upstream.
Recently syzbot reported that unmounting proc when there is an ongoing
inotify watch on the root directory of proc could result in a use
after free when the watch is removed after the unmount of proc
when the watcher exits.
Commit 69879c01a0 ("proc: Remove the now unnecessary internal mount
of proc") made it easier to unmount proc and allowed syzbot to see the
problem, but looking at the code it has been around for a long time.
Looking at the code the fsnotify watch should have been removed by
fsnotify_sb_delete in generic_shutdown_super. Unfortunately the inode
was allocated with new_inode_pseudo instead of new_inode so the inode
was not on the sb->s_inodes list. Which prevented
fsnotify_unmount_inodes from finding the inode and removing the watch
as well as made it so the "VFS: Busy inodes after unmount" warning
could not find the inodes to warn about them.
Make all of the inodes in proc visible to generic_shutdown_super,
and fsnotify_sb_delete by using new_inode instead of new_inode_pseudo.
The only functional difference is that new_inode places the inodes
on the sb->s_inodes list.
I wrote a small test program and I can verify that without changes it
can trigger this issue, and by replacing new_inode_pseudo with
new_inode the issues goes away.
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/000000000000d788c905a7dfa3f4@google.com
Reported-by: syzbot+7d2debdcdb3cb93c1e5e@syzkaller.appspotmail.com
Fixes: 0097875bd4 ("proc: Implement /proc/thread-self to point at the directory of the current thread")
Fixes: 021ada7dff ("procfs: switch /proc/self away from proc_dir_entry")
Fixes: 51f0885e54 ("vfs,proc: guarantee unique inodes in /proc")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bdebd6a283 upstream.
remap_vmalloc_range() has had various issues with the bounds checks it
promises to perform ("This function checks that addr is a valid
vmalloc'ed area, and that it is big enough to cover the vma") over time,
e.g.:
- not detecting pgoff<<PAGE_SHIFT overflow
- not detecting (pgoff<<PAGE_SHIFT)+usize overflow
- not checking whether addr and addr+(pgoff<<PAGE_SHIFT) are the same
vmalloc allocation
- comparing a potentially wildly out-of-bounds pointer with the end of
the vmalloc region
In particular, since commit fc9702273e ("bpf: Add mmap() support for
BPF_MAP_TYPE_ARRAY"), unprivileged users can cause kernel null pointer
dereferences by calling mmap() on a BPF map with a size that is bigger
than the distance from the start of the BPF map to the end of the
address space.
This could theoretically be used as a kernel ASLR bypass, by using
whether mmap() with a given offset oopses or returns an error code to
perform a binary search over the possible address range.
To allow remap_vmalloc_range_partial() to verify that addr and
addr+(pgoff<<PAGE_SHIFT) are in the same vmalloc region, pass the offset
to remap_vmalloc_range_partial() instead of adding it to the pointer in
remap_vmalloc_range().
In remap_vmalloc_range_partial(), fix the check against
get_vm_area_size() by using size comparisons instead of pointer
comparisons, and add checks for pgoff.
Fixes: 833423143c ("[PATCH] mm: introduce remap_vmalloc_range()")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@chromium.org>
Link: http://lkml.kernel.org/r/20200415222312.236431-1-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PD#TV-9668
Problem:
If sp address is in linear mapping range, check_sp_fault_again
function in vmap fault handler will still map a new page for it.
This will cause some data in R/W section polluted.
Solution:
Avoid map page if sp is in linear range.
Verify:
TL1 x301
Change-Id: I0e02a2048b586854c528cd3eeafb725751b9dc82
Signed-off-by: Tao Zeng <tao.zeng@amlogic.com>
commit 04f5866e41 upstream.
The core dumping code has always run without holding the mmap_sem for
writing, despite that is the only way to ensure that the entire vma
layout will not change from under it. Only using some signal
serialization on the processes belonging to the mm is not nearly enough.
This was pointed out earlier. For example in Hugh's post from Jul 2017:
https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils
"Not strictly relevant here, but a related note: I was very surprised
to discover, only quite recently, how handle_mm_fault() may be called
without down_read(mmap_sem) - when core dumping. That seems a
misguided optimization to me, which would also be nice to correct"
In particular because the growsdown and growsup can move the
vm_start/vm_end the various loops the core dump does around the vma will
not be consistent if page faults can happen concurrently.
Pretty much all users calling mmget_not_zero()/get_task_mm() and then
taking the mmap_sem had the potential to introduce unexpected side
effects in the core dumping code.
Adding mmap_sem for writing around the ->core_dump invocation is a
viable long term fix, but it requires removing all copy user and page
faults and to replace them with get_dump_page() for all binary formats
which is not suitable as a short term fix.
For the time being this solution manually covers the places that can
confuse the core dump either by altering the vma layout or the vma flags
while it runs. Once ->core_dump runs under mmap_sem for writing the
function mmget_still_valid() can be dropped.
Allowing mmap_sem protected sections to run in parallel with the
coredump provides some minor parallelism advantage to the swapoff code
(which seems to be safe enough by never mangling any vma field and can
keep doing swapins in parallel to the core dumping) and to some other
corner case.
In order to facilitate the backporting I added "Fixes: 86039bd3b4e6"
however the side effect of this same race condition in /proc/pid/mem
should be reproducible since before 2.6.12-rc2 so I couldn't add any
other "Fixes:" because there's no hash beyond the git genesis commit.
Because find_extend_vma() is the only location outside of the process
context that could modify the "mm" structures under mmap_sem for
reading, by adding the mmget_still_valid() check to it, all other cases
that take the mmap_sem for reading don't need the new check after
mmget_not_zero()/get_task_mm(). The expand_stack() in page fault
context also doesn't need the new check, because all tasks under core
dumping are frozen.
Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com
Fixes: 86039bd3b4 ("userfaultfd: add new syscall to provide memory externalization")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[akaher@vmware.com: stable 4.9 backport
- handle binder_update_page_range - mhocko@suse.com]
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5ec27ec735 upstream.
Normally, the inode's i_uid/i_gid are translated relative to s_user_ns,
but this is not a correct behavior for proc. Since sysctl permission
check in test_perm is done against GLOBAL_ROOT_[UG]ID, it makes more
sense to use these values in u_[ug]id of proc inodes. In other words:
although uid/gid in the inode is not read during test_perm, the inode
logically belongs to the root of the namespace. I have confirmed this
with Eric Biederman at LPC and in this thread:
https://lore.kernel.org/lkml/87k1kzjdff.fsf@xmission.com
Consequences
============
Since the i_[ug]id values of proc nodes are not used for permissions
checks, this change usually makes no functional difference. However, it
causes an issue in a setup where:
* a namespace container is created without root user in container -
hence the i_[ug]id of proc nodes are set to INVALID_[UG]ID
* container creator tries to configure it by writing /proc/sys files,
e.g. writing /proc/sys/kernel/shmmax to configure shared memory limit
Kernel does not allow to open an inode for writing if its i_[ug]id are
invalid, making it impossible to write shmmax and thus - configure the
container.
Using a container with no root mapping is apparently rare, but we do use
this configuration at Google. Also, we use a generic tool to configure
the container limits, and the inability to write any of them causes a
failure.
History
=======
The invalid uids/gids in inodes first appeared due to 8175435777 (fs:
Update i_[ug]id_(read|write) to translate relative to s_user_ns).
However, AFAIK, this did not immediately cause any issues. The
inability to write to these "invalid" inodes was only caused by a later
commit 0bd23d09b8 (vfs: Don't modify inodes with a uid or gid unknown
to the vfs).
Tested: Used a repro program that creates a user namespace without any
mapping and stat'ed /proc/$PID/root/proc/sys/kernel/shmmax from outside.
Before the change, it shows the overflow uid, with the change it's 0.
The overflow uid indicates that the uid in the inode is not correct and
thus it is not possible to open the file for writing.
Link: http://lkml.kernel.org/r/20190708115130.250149-1-rburny@google.com
Fixes: 0bd23d09b8 ("vfs: Don't modify inodes with a uid or gid unknown to the vfs")
Signed-off-by: Radoslaw Burny <rburny@google.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: John Sperbeck <jsperbeck@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <stable@vger.kernel.org> [4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If CONFIG_SECCOMP=n, /proc/self/status includes an empty line. This causes
the iotop application to bail out with an error message.
File "/usr/local/lib64/python2.7/site-packages/iotop/data.py", line 196,
in parse_proc_pid_status
key, value = line.split(':\t', 1)
ValueError: need more than 1 value to unpack
The problem is seen in v4.9.y but not upstream because commit af884cd4a5
("proc: report no_new_privs state") has not been backported to v4.9.y.
The backport of commit fae1fa0fc6 ("proc: Provide details on speculation
flaw mitigations") tried to address the resulting differences but was
wrong, introducing the problem.
Fixes: 51ef9af2a3 ("proc: Provide details on speculation flaw mitigations")
Cc: Kees Cook <keescook@chromium.org>
Cc: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Kees Cook <keescook@chromium.org>
commit ea5751ccd6 upstream.
proc_sys_lookup can fail with ENOMEM instead of ENOENT when the
corresponding sysctl table is being unregistered. In our case we see
this upon opening /proc/sys/net/*/conf files while network interfaces
are being deleted, which confuses our configuration daemon.
The problem was successfully reproduced and this fix tested on v4.9.122
and v4.20-rc6.
v2: return ERR_PTRs in all cases when proc_sys_make_inode fails instead
of mixing them with NULL. Thanks Al Viro for the feedback.
Fixes: ace0c791e6 ("proc/sysctl: Don't grab i_lock under sysctl_lock.")
Cc: stable@vger.kernel.org
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PD#SWPL-1219
Problem:
On arm64, thread stack is 16KB for each task. If running task number
is large, this type of memory may over 40MB. It's a large amount on
small memory platform. But most case thread only use less 4KB stack.
It's waste of memory and we need optimize it.
Solution:
1. Pre-allocate a vmalloc address space for task stack;
2. Only map 1st page for stack and handle page fault in EL1
when stack growth triggered exception;
3. handle stack switch for exception.
Verify:
p212
Change-Id: I47f511ccfa2868d982bc10a820ed6435b6d52ba9
Signed-off-by: tao zeng <tao.zeng@amlogic.com>
commit f8a00cef17 upstream.
Currently, you can use /proc/self/task/*/stack to cause a stack walk on
a task you control while it is running on another CPU. That means that
the stack can change under the stack walker. The stack walker does
have guards against going completely off the rails and into random
kernel memory, but it can interpret random data from your kernel stack
as instruction pointers and stack pointers. This can cause exposure of
kernel stack contents to userspace.
Restrict the ability to inspect kernel stacks of arbitrary tasks to root
in order to prevent a local attacker from exploiting racy stack unwinding
to leak kernel task stack contents. See the added comment for a longer
rationale.
There don't seem to be any users of this userspace API that can't
gracefully bail out if reading from the file fails. Therefore, I believe
that this change is unlikely to break things. In the case that this patch
does end up needing a revert, the next-best solution might be to fake a
single-entry stack based on wchan.
Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com
Fixes: 2ec220e27f ("proc: add /proc/*/stack")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ken Chen <kenchen@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2fd1d2c4ce upstream.
Andrei Vagin writes:
FYI: This bug has been reproduced on 4.11.7
> BUG: Dentry ffff895a3dd01240{i=4e7c09a,n=lo} still in use (1) [unmount of proc proc]
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 13588 at fs/dcache.c:1445 umount_check+0x6e/0x80
> CPU: 1 PID: 13588 Comm: kworker/1:1 Not tainted 4.11.7-200.fc25.x86_64 #1
> Hardware name: CompuLab sbc-flt1/fitlet, BIOS SBCFLT_0.08.04 06/27/2015
> Workqueue: events proc_cleanup_work
> Call Trace:
> dump_stack+0x63/0x86
> __warn+0xcb/0xf0
> warn_slowpath_null+0x1d/0x20
> umount_check+0x6e/0x80
> d_walk+0xc6/0x270
> ? dentry_free+0x80/0x80
> do_one_tree+0x26/0x40
> shrink_dcache_for_umount+0x2d/0x90
> generic_shutdown_super+0x1f/0xf0
> kill_anon_super+0x12/0x20
> proc_kill_sb+0x40/0x50
> deactivate_locked_super+0x43/0x70
> deactivate_super+0x5a/0x60
> cleanup_mnt+0x3f/0x90
> mntput_no_expire+0x13b/0x190
> kern_unmount+0x3e/0x50
> pid_ns_release_proc+0x15/0x20
> proc_cleanup_work+0x15/0x20
> process_one_work+0x197/0x450
> worker_thread+0x4e/0x4a0
> kthread+0x109/0x140
> ? process_one_work+0x450/0x450
> ? kthread_park+0x90/0x90
> ret_from_fork+0x2c/0x40
> ---[ end trace e1c109611e5d0b41 ]---
> VFS: Busy inodes after unmount of proc. Self-destruct in 5 seconds. Have a nice day...
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: _raw_spin_lock+0xc/0x30
> PGD 0
Fix this by taking a reference to the super block in proc_sys_prune_dcache.
The superblock reference is the core of the fix however the sysctl_inodes
list is converted to a hlist so that hlist_del_init_rcu may be used. This
allows proc_sys_prune_dache to remove inodes the sysctl_inodes list, while
not causing problems for proc_sys_evict_inode when if it later choses to
remove the inode from the sysctl_inodes list. Removing inodes from the
sysctl_inodes list allows proc_sys_prune_dcache to have a progress
guarantee, while still being able to drop all locks. The fact that
head->unregistering is set in start_unregistering ensures that no more
inodes will be added to the the sysctl_inodes list.
Previously the code did a dance where it delayed calling iput until the
next entry in the list was being considered to ensure the inode remained on
the sysctl_inodes list until the next entry was walked to. The structure
of the loop in this patch does not need that so is much easier to
understand and maintain.
Cc: stable@vger.kernel.org
Reported-by: Andrei Vagin <avagin@gmail.com>
Tested-by: Andrei Vagin <avagin@openvz.org>
Fixes: ace0c791e6 ("proc/sysctl: Don't grab i_lock under sysctl_lock.")
Fixes: d6cffbbe9a ("proc/sysctl: prune stale dentries during unregistering")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ace0c791e6 upstream.
Konstantin Khlebnikov <khlebnikov@yandex-team.ru> writes:
> This patch has locking problem. I've got lockdep splat under LTP.
>
> [ 6633.115456] ======================================================
> [ 6633.115502] [ INFO: possible circular locking dependency detected ]
> [ 6633.115553] 4.9.10-debug+ #9 Tainted: G L
> [ 6633.115584] -------------------------------------------------------
> [ 6633.115627] ksm02/284980 is trying to acquire lock:
> [ 6633.115659] (&sb->s_type->i_lock_key#4){+.+...}, at: [<ffffffff816bc1ce>] igrab+0x1e/0x80
> [ 6633.115834] but task is already holding lock:
> [ 6633.115882] (sysctl_lock){+.+...}, at: [<ffffffff817e379b>] unregister_sysctl_table+0x6b/0x110
> [ 6633.116026] which lock already depends on the new lock.
> [ 6633.116026]
> [ 6633.116080]
> [ 6633.116080] the existing dependency chain (in reverse order) is:
> [ 6633.116117]
> -> #2 (sysctl_lock){+.+...}:
> -> #1 (&(&dentry->d_lockref.lock)->rlock){+.+...}:
> -> #0 (&sb->s_type->i_lock_key#4){+.+...}:
>
> d_lock nests inside i_lock
> sysctl_lock nests inside d_lock in d_compare
>
> This patch adds i_lock nesting inside sysctl_lock.
Al Viro <viro@ZenIV.linux.org.uk> replied:
> Once ->unregistering is set, you can drop sysctl_lock just fine. So I'd
> try something like this - use rcu_read_lock() in proc_sys_prune_dcache(),
> drop sysctl_lock() before it and regain after. Make sure that no inodes
> are added to the list ones ->unregistering has been set and use RCU list
> primitives for modifying the inode list, with sysctl_lock still used to
> serialize its modifications.
>
> Freeing struct inode is RCU-delayed (see proc_destroy_inode()), so doing
> igrab() is safe there. Since we don't drop inode reference until after we'd
> passed beyond it in the list, list_for_each_entry_rcu() should be fine.
I agree with Al Viro's analsysis of the situtation.
Fixes: d6cffbbe9a ("proc/sysctl: prune stale dentries during unregistering")
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Tested-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d6cffbbe9a upstream.
Currently unregistering sysctl table does not prune its dentries.
Stale dentries could slowdown sysctl operations significantly.
For example, command:
# for i in {1..100000} ; do unshare -n -- sysctl -a &> /dev/null ; done
creates a millions of stale denties around sysctls of loopback interface:
# sysctl fs.dentry-state
fs.dentry-state = 25812579 24724135 45 0 0 0
All of them have matching names thus lookup have to scan though whole
hash chain and call d_compare (proc_sys_compare) which checks them
under system-wide spinlock (sysctl_lock).
# time sysctl -a > /dev/null
real 1m12.806s
user 0m0.016s
sys 1m12.400s
Currently only memory reclaimer could remove this garbage.
But without significant memory pressure this never happens.
This patch collects sysctl inodes into list on sysctl table header and
prunes all their dentries once that table unregisters.
Konstantin Khlebnikov <khlebnikov@yandex-team.ru> writes:
> On 10.02.2017 10:47, Al Viro wrote:
>> how about >> the matching stats *after* that patch?
>
> dcache size doesn't grow endlessly, so stats are fine
>
> # sysctl fs.dentry-state
> fs.dentry-state = 92712 58376 45 0 0 0
>
> # time sysctl -a &>/dev/null
>
> real 0m0.013s
> user 0m0.004s
> sys 0m0.008s
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Changes in 4.9.104
MIPS: c-r4k: Fix data corruption related to cache coherence
MIPS: ptrace: Expose FIR register through FP regset
MIPS: Fix ptrace(2) PTRACE_PEEKUSR and PTRACE_POKEUSR accesses to o32 FGRs
KVM: Fix spelling mistake: "cop_unsuable" -> "cop_unusable"
affs_lookup(): close a race with affs_remove_link()
aio: fix io_destroy(2) vs. lookup_ioctx() race
ALSA: timer: Fix pause event notification
do d_instantiate/unlock_new_inode combinations safely
mmc: sdhci-iproc: remove hard coded mmc cap 1.8v
mmc: sdhci-iproc: fix 32bit writes for TRANSFER_MODE register
libata: Blacklist some Sandisk SSDs for NCQ
libata: blacklist Micron 500IT SSD with MU01 firmware
xen-swiotlb: fix the check condition for xen_swiotlb_free_coherent
drm/vmwgfx: Fix 32-bit VMW_PORT_HB_[IN|OUT] macros
IB/hfi1: Use after free race condition in send context error path
Revert "ipc/shm: Fix shmat mmap nil-page protection"
ipc/shm: fix shmat() nil address after round-down when remapping
kasan: fix memory hotplug during boot
kernel/sys.c: fix potential Spectre v1 issue
kernel/signal.c: avoid undefined behaviour in kill_something_info
KVM/VMX: Expose SSBD properly to guests
KVM: s390: vsie: fix < 8k check for the itdba
KVM: x86: Update cpuid properly when CR4.OSXAVE or CR4.PKE is changed
kvm: x86: IA32_ARCH_CAPABILITIES is always supported
firewire-ohci: work around oversized DMA reads on JMicron controllers
x86/tsc: Allow TSC calibration without PIT
NFSv4: always set NFS_LOCK_LOST when a lock is lost.
ALSA: hda - Use IS_REACHABLE() for dependency on input
kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl
netfilter: ipv6: nf_defrag: Pass on packets to stack per RFC2460
tracing/hrtimer: Fix tracing bugs by taking all clock bases and modes into account
PCI: Add function 1 DMA alias quirk for Marvell 9128
Input: psmouse - fix Synaptics detection when protocol is disabled
i40iw: Zero-out consumer key on allocate stag for FMR
tools lib traceevent: Simplify pointer print logic and fix %pF
perf callchain: Fix attr.sample_max_stack setting
tools lib traceevent: Fix get_field_str() for dynamic strings
perf record: Fix failed memory allocation for get_cpuid_str
iommu/vt-d: Use domain instead of cache fetching
dm thin: fix documentation relative to low water mark threshold
net: stmmac: dwmac-meson8b: fix setting the RGMII TX clock on Meson8b
net: stmmac: dwmac-meson8b: propagate rate changes to the parent clock
nfs: Do not convert nfs_idmap_cache_timeout to jiffies
watchdog: sp5100_tco: Fix watchdog disable bit
kconfig: Don't leak main menus during parsing
kconfig: Fix automatic menu creation mem leak
kconfig: Fix expr_free() E_NOT leak
mac80211_hwsim: fix possible memory leak in hwsim_new_radio_nl()
ipmi/powernv: Fix error return code in ipmi_powernv_probe()
Btrfs: set plug for fsync
btrfs: Fix out of bounds access in btrfs_search_slot
Btrfs: fix scrub to repair raid6 corruption
btrfs: fail mount when sb flag is not in BTRFS_SUPER_FLAG_SUPP
HID: roccat: prevent an out of bounds read in kovaplus_profile_activated()
fm10k: fix "failed to kill vid" message for VF
device property: Define type of PROPERTY_ENRTY_*() macros
jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path
powerpc/numa: Use ibm,max-associativity-domains to discover possible nodes
powerpc/numa: Ensure nodes initialized for hotplug
RDMA/mlx5: Avoid memory leak in case of XRCD dealloc failure
ntb_transport: Fix bug with max_mw_size parameter
gianfar: prevent integer wrapping in the rx handler
tcp_nv: fix potential integer overflow in tcpnv_acked
kvm: Map PFN-type memory regions as writable (if possible)
ocfs2: return -EROFS to mount.ocfs2 if inode block is invalid
ocfs2/acl: use 'ip_xattr_sem' to protect getting extended attribute
ocfs2: return error when we attempt to access a dirty bh in jbd2
mm/mempolicy: fix the check of nodemask from user
mm/mempolicy: add nodes_empty check in SYSC_migrate_pages
asm-generic: provide generic_pmdp_establish()
sparc64: update pmdp_invalidate() to return old pmd value
mm: thp: use down_read_trylock() in khugepaged to avoid long block
mm: pin address_space before dereferencing it while isolating an LRU page
mm/fadvise: discard partial page if endbyte is also EOF
openvswitch: Remove padding from packet before L3+ conntrack processing
IB/ipoib: Fix for potential no-carrier state
drm/nouveau/pmu/fuc: don't use movw directly anymore
netfilter: ipv6: nf_defrag: Kill frag queue on RFC2460 failure
x86/power: Fix swsusp_arch_resume prototype
firmware: dmi_scan: Fix handling of empty DMI strings
ACPI: processor_perflib: Do not send _PPC change notification if not ready
ACPI / scan: Use acpi_bus_get_status() to initialize ACPI_TYPE_DEVICE devs
bpf: fix selftests/bpf test_kmod.sh failure when CONFIG_BPF_JIT_ALWAYS_ON=y
MIPS: generic: Fix machine compatible matching
MIPS: TXx9: use IS_BUILTIN() for CONFIG_LEDS_CLASS
xen-netfront: Fix race between device setup and open
xen/grant-table: Use put_page instead of free_page
RDS: IB: Fix null pointer issue
arm64: spinlock: Fix theoretical trylock() A-B-A with LSE atomics
proc: fix /proc/*/map_files lookup
cifs: silence compiler warnings showing up with gcc-8.0.0
bcache: properly set task state in bch_writeback_thread()
bcache: fix for allocator and register thread race
bcache: fix for data collapse after re-attaching an attached device
bcache: return attach error when no cache set exist
tools/libbpf: handle issues with bpf ELF objects containing .eh_frames
bpf: fix rlimit in reuseport net selftest
vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page
locking/qspinlock: Ensure node->count is updated before initialising node
irqchip/gic-v3: Ignore disabled ITS nodes
cpumask: Make for_each_cpu_wrap() available on UP as well
irqchip/gic-v3: Change pr_debug message to pr_devel
ARC: Fix malformed ARC_EMUL_UNALIGNED default
ptr_ring: prevent integer overflow when calculating size
libata: Fix compile warning with ATA_DEBUG enabled
selftests: pstore: Adding config fragment CONFIG_PSTORE_RAM=m
selftests: memfd: add config fragment for fuse
ARM: OMAP2+: timer: fix a kmemleak caused in omap_get_timer_dt
ARM: OMAP3: Fix prm wake interrupt for resume
ARM: OMAP1: clock: Fix debugfs_create_*() usage
ibmvnic: Free RX socket buffer in case of adapter error
iwlwifi: mvm: fix security bug in PN checking
iwlwifi: mvm: always init rs with 20mhz bandwidth rates
NFC: llcp: Limit size of SDP URI
rxrpc: Work around usercopy check
mac80211: round IEEE80211_TX_STATUS_HEADROOM up to multiple of 4
mac80211: fix a possible leak of station stats
mac80211: fix calling sleeping function in atomic context
mac80211: Do not disconnect on invalid operating class
md raid10: fix NULL deference in handle_write_completed()
drm/exynos: g2d: use monotonic timestamps
drm/exynos: fix comparison to bitshift when dealing with a mask
locking/xchg/alpha: Add unconditional memory barrier to cmpxchg()
md: raid5: avoid string overflow warning
kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE
powerpc/bpf/jit: Fix 32-bit JIT for seccomp_data access
s390/cio: fix ccw_device_start_timeout API
s390/cio: fix return code after missing interrupt
s390/cio: clear timer when terminating driver I/O
PKCS#7: fix direct verification of SignerInfo signature
ARM: OMAP: Fix dmtimer init for omap1
smsc75xx: fix smsc75xx_set_features()
regulatory: add NUL to request alpha2
integrity/security: fix digsig.c build error with header file
locking/xchg/alpha: Fix xchg() and cmpxchg() memory ordering bugs
x86/topology: Update the 'cpu cores' field in /proc/cpuinfo correctly across CPU hotplug operations
mac80211: drop frames with unexpected DS bits from fast-rx to slow path
arm64: fix unwind_frame() for filtered out fn for function graph tracing
macvlan: fix use-after-free in macvlan_common_newlink()
kvm: fix warning for CONFIG_HAVE_KVM_EVENTFD builds
fs: dcache: Avoid livelock between d_alloc_parallel and __d_add
fs: dcache: Use READ_ONCE when accessing i_dir_seq
md: fix a potential deadlock of raid5/raid10 reshape
md/raid1: fix NULL pointer dereference
batman-adv: fix packet checksum in receive path
batman-adv: invalidate checksum on fragment reassembly
netfilter: ebtables: convert BUG_ONs to WARN_ONs
batman-adv: Ignore invalid batadv_iv_gw during netlink send
batman-adv: Ignore invalid batadv_v_gw during netlink send
batman-adv: Fix netlink dumping of BLA claims
batman-adv: Fix netlink dumping of BLA backbones
nvme-pci: Fix nvme queue cleanup if IRQ setup fails
clocksource/drivers/fsl_ftm_timer: Fix error return checking
ceph: fix dentry leak when failing to init debugfs
ARM: orion5x: Revert commit 4904dbda41.
qrtr: add MODULE_ALIAS macro to smd
r8152: fix tx packets accounting
virtio-gpu: fix ioctl and expose the fixed status to userspace.
dmaengine: rcar-dmac: fix max_chunk_size for R-Car Gen3
bcache: fix kcrashes with fio in RAID5 backend dev
ip6_tunnel: fix IFLA_MTU ignored on NEWLINK
sit: fix IFLA_MTU ignored on NEWLINK
ARM: dts: NSP: Fix amount of RAM on BCM958625HR
powerpc/boot: Fix random libfdt related build errors
gianfar: Fix Rx byte accounting for ndev stats
net/tcp/illinois: replace broken algorithm reference link
nvmet: fix PSDT field check in command format
xen/pirq: fix error path cleanup when binding MSIs
drm/sun4i: Fix dclk_set_phase
Btrfs: send, fix issuing write op when processing hole in no data mode
selftests/powerpc: Skip the subpage_prot tests if the syscall is unavailable
KVM: PPC: Book3S HV: Fix VRMA initialization with 2MB or 1GB memory backing
iwlwifi: mvm: fix TX of CCMP 256
watchdog: f71808e_wdt: Fix magic close handling
watchdog: sbsa: use 32-bit read for WCV
batman-adv: Fix multicast packet loss with a single WANT_ALL_IPV4/6 flag
e1000e: Fix check_for_link return value with autoneg off
e1000e: allocate ring descriptors with dma_zalloc_coherent
ia64/err-inject: Use get_user_pages_fast()
RDMA/qedr: Fix kernel panic when running fio over NFSoRDMA
RDMA/qedr: Fix iWARP write and send with immediate
IB/mlx4: Fix corruption of RoCEv2 IPv4 GIDs
IB/mlx4: Include GID type when deleting GIDs from HW table under RoCE
IB/mlx5: Fix an error code in __mlx5_ib_modify_qp()
fbdev: Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in sbusfb_ioctl_helper().
fsl/fman: avoid sleeping in atomic context while adding an address
net: qcom/emac: Use proper free methods during TX
net: smsc911x: Fix unload crash when link is up
IB/core: Fix possible crash to access NULL netdev
xen: xenbus: use put_device() instead of kfree()
arm64: Relax ARM_SMCCC_ARCH_WORKAROUND_1 discovery
dmaengine: mv_xor_v2: Fix clock resource by adding a register clock
netfilter: ebtables: fix erroneous reject of last rule
bnxt_en: Check valid VNIC ID in bnxt_hwrm_vnic_set_tpa().
workqueue: use put_device() instead of kfree()
ipv4: lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmtu
sunvnet: does not support GSO for sctp
drm/imx: move arming of the vblank event to atomic_flush
net: Fix vlan untag for bridge and vlan_dev with reorder_hdr off
batman-adv: fix header size check in batadv_dbg_arp()
batman-adv: Fix skbuff rcsum on packet reroute
vti4: Don't count header length twice on tunnel setup
vti4: Don't override MTU passed on link creation via IFLA_MTU
perf/cgroup: Fix child event counting bug
brcmfmac: Fix check for ISO3166 code
kbuild: make scripts/adjust_autoksyms.sh robust against timestamp races
RDMA/ucma: Correct option size check using optlen
RDMA/qedr: fix QP's ack timeout configuration
RDMA/qedr: Fix rc initialization on CNQ allocation failure
mm/mempolicy.c: avoid use uninitialized preferred_node
mm, thp: do not cause memcg oom for thp
selftests: ftrace: Add probe event argument syntax testcase
selftests: ftrace: Add a testcase for string type with kprobe_event
selftests: ftrace: Add a testcase for probepoint
batman-adv: fix multicast-via-unicast transmission with AP isolation
batman-adv: fix packet loss for broadcasted DHCP packets to a server
ARM: 8748/1: mm: Define vdso_start, vdso_end as array
net: qmi_wwan: add BroadMobi BM806U 2020:2033
perf/x86/intel: Fix linear IP of PEBS real_ip on Haswell and later CPUs
llc: properly handle dev_queue_xmit() return value
builddeb: Fix header package regarding dtc source links
mm/kmemleak.c: wait for scan completion before disabling free
net: Fix untag for vlan packets without ethernet header
net: mvneta: fix enable of all initialized RXQs
sh: fix debug trap failure to process signals before return to user
nvme: don't send keep-alives to the discovery controller
x86/pgtable: Don't set huge PUD/PMD on non-leaf entries
x86/mm: Do not forbid _PAGE_RW before init for __ro_after_init
fs/proc/proc_sysctl.c: fix potential page fault while unregistering sysctl table
swap: divide-by-zero when zero length swap file on ssd
sr: get/drop reference to device in revalidate and check_events
Force log to disk before reading the AGF during a fstrim
cpufreq: CPPC: Initialize shared perf capabilities of CPUs
dp83640: Ensure against premature access to PHY registers after reset
mm/ksm: fix interaction with THP
mm: fix races between address_space dereference and free in page_evicatable
Btrfs: bail out on error during replay_dir_deletes
Btrfs: fix NULL pointer dereference in log_dir_items
btrfs: Fix possible softlock on single core machines
ocfs2/dlm: don't handle migrate lockres if already in shutdown
sched/rt: Fix rq->clock_update_flags < RQCF_ACT_SKIP warning
KVM: VMX: raise internal error for exception during invalid protected mode state
fscache: Fix hanging wait on page discarded by writeback
sparc64: Make atomic_xchg() an inline function rather than a macro.
net: bgmac: Fix endian access in bgmac_dma_tx_ring_free()
btrfs: tests/qgroup: Fix wrong tree backref level
Btrfs: fix copy_items() return value when logging an inode
btrfs: fix lockdep splat in btrfs_alloc_subvolume_writers
rxrpc: Fix Tx ring annotation after initial Tx failure
rxrpc: Don't treat call aborts as conn aborts
xen/acpi: off by one in read_acpi_id()
drivers: macintosh: rack-meter: really fix bogus memsets
ACPI: acpi_pad: Fix memory leak in power saving threads
powerpc/mpic: Check if cpu_possible() in mpic_physmask()
m68k: set dma and coherent masks for platform FEC ethernets
parisc/pci: Switch LBA PCI bus from Hard Fail to Soft Fail mode
hwmon: (nct6775) Fix writing pwmX_mode
powerpc/perf: Prevent kernel address leak to userspace via BHRB buffer
powerpc/perf: Fix kernel address leak via sampling registers
tools/thermal: tmon: fix for segfault
selftests: Print the test we're running to /dev/kmsg
net/mlx5: Protect from command bit overflow
ath10k: Fix kernel panic while using worker (ath10k_sta_rc_update_wk)
cxgb4: Setup FW queues before registering netdev
ima: Fallback to the builtin hash algorithm
virtio-net: Fix operstate for virtio when no VIRTIO_NET_F_STATUS
arm: dts: socfpga: fix GIC PPI warning
cpufreq: cppc_cpufreq: Fix cppc_cpufreq_init() failure path
zorro: Set up z->dev.dma_mask for the DMA API
bcache: quit dc->writeback_thread when BCACHE_DEV_DETACHING is set
ACPICA: Events: add a return on failure from acpi_hw_register_read
ACPICA: acpi: acpica: fix acpi operand cache leak in nseval.c
cxgb4: Fix queue free path of ULD drivers
i2c: mv64xxx: Apply errata delay only in standard mode
KVM: lapic: stop advertising DIRECTED_EOI when in-kernel IOAPIC is in use
perf top: Fix top.call-graph config option reading
perf stat: Fix core dump when flag T is used
IB/core: Honor port_num while resolving GID for IB link layer
regulator: gpio: Fix some error handling paths in 'gpio_regulator_probe()'
spi: bcm-qspi: fIX some error handling paths
MIPS: ath79: Fix AR724X_PLL_REG_PCIE_CONFIG offset
PCI: Restore config space on runtime resume despite being unbound
ipmi_ssif: Fix kernel panic at msg_done_handler
powerpc: Add missing prototype for arch_irq_work_raise()
f2fs: fix to check extent cache in f2fs_drop_extent_tree
perf/core: Fix perf_output_read_group()
drm/panel: simple: Fix the bus format for the Ontat panel
hwmon: (pmbus/max8688) Accept negative page register values
hwmon: (pmbus/adm1275) Accept negative page register values
perf/x86/intel: Properly save/restore the PMU state in the NMI handler
cdrom: do not call check_disk_change() inside cdrom_open()
perf/x86/intel: Fix large period handling on Broadwell CPUs
perf/x86/intel: Fix event update for auto-reload
arm64: dts: qcom: Fix SPI5 config on MSM8996
soc: qcom: wcnss_ctrl: Fix increment in NV upload
gfs2: Fix fallocate chunk size
x86/devicetree: Initialize device tree before using it
x86/devicetree: Fix device IRQ settings in DT
ALSA: vmaster: Propagate slave error
dmaengine: pl330: fix a race condition in case of threaded irqs
dmaengine: rcar-dmac: Check the done lists in rcar_dmac_chan_get_residue()
enic: enable rq before updating rq descriptors
hwrng: stm32 - add reset during probe
dmaengine: qcom: bam_dma: get num-channels and num-ees from dt
net: stmmac: ensure that the device has released ownership before reading data
net: stmmac: ensure that the MSS desc is the last desc to set the own bit
cpufreq: Reorder cpufreq_online() error code path
PCI: Add function 1 DMA alias quirk for Marvell 88SE9220
udf: Provide saner default for invalid uid / gid
ARM: dts: bcm283x: Fix probing of bcm2835-i2s
audit: return on memory error to avoid null pointer dereference
rcu: Call touch_nmi_watchdog() while printing stall warnings
pinctrl: sh-pfc: r8a7796: Fix MOD_SEL register pin assignment for SSI pins group
MIPS: Octeon: Fix logging messages with spurious periods after newlines
drm/rockchip: Respect page offset for PRIME mmap calls
x86/apic: Set up through-local-APIC mode on the boot CPU if 'noapic' specified
perf tests: Use arch__compare_symbol_names to compare symbols
perf report: Fix memory corruption in --branch-history mode --branch-history
selftests/net: fixes psock_fanout eBPF test case
netlabel: If PF_INET6, check sk_buff ip header version
regmap: Correct comparison in regmap_cached
ARM: dts: imx7d: cl-som-imx7: fix pinctrl_enet
ARM: dts: porter: Fix HDMI output routing
regulator: of: Add a missing 'of_node_put()' in an error handling path of 'of_regulator_match()'
pinctrl: msm: Use dynamic GPIO numbering
kdb: make "mdr" command repeat
Linux 4.9.104
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
[ Upstream commit ac7f1061c2 ]
Current code does:
if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
However sscanf() is broken garbage.
It silently accepts whitespace between format specifiers
(did you know that?).
It silently accepts valid strings which result in integer overflow.
Do not use sscanf() for any even remotely reliable parsing code.
OK
# readlink '/proc/1/map_files/55a23af39000-55a23b05b000'
/lib/systemd/systemd
broken
# readlink '/proc/1/map_files/ 55a23af39000-55a23b05b000'
/lib/systemd/systemd
broken
# readlink '/proc/1/map_files/55a23af39000-55a23b05b000 '
/lib/systemd/systemd
very broken
# readlink '/proc/1/map_files/1000000000000000055a23af39000-55a23b05b000'
/lib/systemd/systemd
Andrei said:
: This patch breaks criu. It was a bug in criu. And this bug is on a minor
: path, which works when memfd_create() isn't available. It is a reason why
: I ask to not backport this patch to stable kernels.
:
: In CRIU this bug can be triggered, only if this patch will be backported
: to a kernel which version is lower than v3.16.
Link: http://lkml.kernel.org/r/20171120212706.GA14325@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When uid_base_stuff has no entries, proc_uid_base_readdir tries to
compute an address before the start of the array. Revise this check to
use uid_base_stuff + nents instead, which makes the code valid
regardless of array size.
Bug: 80158484
Test: No more compiler warning with CONFIG_CPU_FREQ_TIMES=n
Change-Id: I6e55b27c3ba8210cee194f6d27bbd62c0b263796
Signed-off-by: Connor O'Brien <connoro@google.com>
