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When memory is hotplug added or removed the min_free_kbytes should be
recalculated based on what is expected by khugepaged. Currently after
hotplug, min_free_kbytes will be set to a lower default and higher
default set when THP enabled is lost.
This change restores min_free_kbytes as expected for THP consumers.
[vijayb@linux.microsoft.com: v5]
Link: https://lkml.kernel.org/r/1601398153-5517-1-git-send-email-vijayb@linux.microsoft.com
Fixes: f000565adb77 ("thp: set recommended min free kbytes")
Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Allen Pais <apais@microsoft.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/1600305709-2319-2-git-send-email-vijayb@linux.microsoft.com
Link: https://lkml.kernel.org/r/1600204258-13683-1-git-send-email-vijayb@linux.microsoft.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The swap address_space doesn't have host. Thus, it makes kernel crash once
swap write meets error. Fix it.
Fixes: 735e4ae5ba28 ("vfs: track per-sb writeback errors and report them to syncfs")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andres Freund <andres@anarazel.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201010000650.750063-1-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The syzbot reported the below general protection fault:
general protection fault, probably for non-canonical address
0xe00eeaee0000003b: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0x00777770000001d8-0x00777770000001df]
CPU: 1 PID: 10488 Comm: syz-executor721 Not tainted 5.9.0-rc3-syzkaller #0
RIP: 0010:unlink_file_vma+0x57/0xb0 mm/mmap.c:164
Call Trace:
free_pgtables+0x1b3/0x2f0 mm/memory.c:415
exit_mmap+0x2c0/0x530 mm/mmap.c:3184
__mmput+0x122/0x470 kernel/fork.c:1076
mmput+0x53/0x60 kernel/fork.c:1097
exit_mm kernel/exit.c:483 [inline]
do_exit+0xa8b/0x29f0 kernel/exit.c:793
do_group_exit+0x125/0x310 kernel/exit.c:903
get_signal+0x428/0x1f00 kernel/signal.c:2757
arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:136 [inline]
exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:167
syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:242
entry_SYSCALL_64_after_hwframe+0x44/0xa9
It's because the ->mmap() callback can change vma->vm_file and fput the
original file. But the commit d70cec898324 ("mm: mmap: merge vma after
call_mmap() if possible") failed to catch this case and always fput()
the original file, hence add an extra fput().
[ Thanks Hillf for pointing this extra fput() out. ]
Fixes: d70cec898324 ("mm: mmap: merge vma after call_mmap() if possible")
Reported-by: syzbot+c5d5a51dcbb558ca0cb5@syzkaller.appspotmail.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian König <ckoenig.leichtzumerken@gmail.com>
Cc: Hongxiang Lou <louhongxiang@huawei.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Link: https://lkml.kernel.org/r/20200916090733.31427-1-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use my kernel.org address instead of my bootlin.com one.
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20201005164533.16811-1-atenart@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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As more email from git history gets aimed at the OpenWall
kernel-hardening@ list, there has been a desire to separate "new topics"
from "on-going" work.
To handle this, the superset of hardening email topics are now to be
directed to linux-hardening@vger.kernel.org.
Update the MAINTAINERS file and the .mailmap to accomplish this, so that
linux-hardening@ can be treated like any other regular upstream kernel
development list.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: "Tobin C. Harding" <me@tobin.cc>
Cc: Tycho Andersen <tycho@tycho.pizza>
Cc: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/linux-hardening/202010051443.279CC265D@keescook/
Link: https://lkml.kernel.org/r/20201006000012.2768958-1-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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On setxattr() syscall path due to an apprent typo the size of a dynamically
allocated memory chunk for storing struct smb2_file_full_ea_info object is
computed incorrectly, to be more precise the first addend is the size of
a pointer instead of the wanted object size. Coincidentally it makes no
difference on 64-bit platforms, however on 32-bit targets the following
memcpy() writes 4 bytes of data outside of the dynamically allocated memory.
=============================================================================
BUG kmalloc-16 (Not tainted): Redzone overwritten
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: 0x79e69a6f-0x9e5cdecf @offset=368. First byte 0x73 instead of 0xcc
INFO: Slab 0xd36d2454 objects=85 used=51 fp=0xf7d0fc7a flags=0x35000201
INFO: Object 0x6f171df3 @offset=352 fp=0x00000000
Redzone 5d4ff02d: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc ................
Object 6f171df3: 00 00 00 00 00 05 06 00 73 6e 72 75 62 00 66 69 ........snrub.fi
Redzone 79e69a6f: 73 68 32 0a sh2.
Padding 56254d82: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
CPU: 0 PID: 8196 Comm: attr Tainted: G B 5.9.0-rc8+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014
Call Trace:
dump_stack+0x54/0x6e
print_trailer+0x12c/0x134
check_bytes_and_report.cold+0x3e/0x69
check_object+0x18c/0x250
free_debug_processing+0xfe/0x230
__slab_free+0x1c0/0x300
kfree+0x1d3/0x220
smb2_set_ea+0x27d/0x540
cifs_xattr_set+0x57f/0x620
__vfs_setxattr+0x4e/0x60
__vfs_setxattr_noperm+0x4e/0x100
__vfs_setxattr_locked+0xae/0xd0
vfs_setxattr+0x4e/0xe0
setxattr+0x12c/0x1a0
path_setxattr+0xa4/0xc0
__ia32_sys_lsetxattr+0x1d/0x20
__do_fast_syscall_32+0x40/0x70
do_fast_syscall_32+0x29/0x60
do_SYSENTER_32+0x15/0x20
entry_SYSENTER_32+0x9f/0xf2
Fixes: 5517554e4313 ("cifs: Add support for writing attributes on SMB2+")
Signed-off-by: Vladimir Zapolskiy <vladimir@tuxera.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There have been elusive reports of filemap_fault() hitting its
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page) on kernels built
with CONFIG_READ_ONLY_THP_FOR_FS=y.
Suren has hit it on a kernel with CONFIG_READ_ONLY_THP_FOR_FS=y and
CONFIG_NUMA is not set: and he has analyzed it down to how khugepaged
without NUMA reuses the same huge page after collapse_file() failed
(whereas NUMA targets its allocation to the respective node each time).
And most of us were usually testing with CONFIG_NUMA=y kernels.
collapse_file(old start)
new_page = khugepaged_alloc_page(hpage)
__SetPageLocked(new_page)
new_page->index = start // hpage->index=old offset
new_page->mapping = mapping
xas_store(&xas, new_page)
filemap_fault
page = find_get_page(mapping, offset)
// if offset falls inside hpage then
// compound_head(page) == hpage
lock_page_maybe_drop_mmap()
__lock_page(page)
// collapse fails
xas_store(&xas, old page)
new_page->mapping = NULL
unlock_page(new_page)
collapse_file(new start)
new_page = khugepaged_alloc_page(hpage)
__SetPageLocked(new_page)
new_page->index = start // hpage->index=new offset
new_page->mapping = mapping // mapping becomes valid again
// since compound_head(page) == hpage
// page_to_pgoff(page) got changed
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset)
An initial patch replaced __SetPageLocked() by lock_page(), which did
fix the race which Suren illustrates above. But testing showed that it's
not good enough: if the racing task's __lock_page() gets delayed long
after its find_get_page(), then it may follow collapse_file(new start)'s
successful final unlock_page(), and crash on the same VM_BUG_ON_PAGE.
It could be fixed by relaxing filemap_fault()'s VM_BUG_ON_PAGE to a
check and retry (as is done for mapping), with similar relaxations in
find_lock_entry() and pagecache_get_page(): but it's not obvious what
else might get caught out; and khugepaged non-NUMA appears to be unique
in exposing a page to page cache, then revoking, without going through
a full cycle of freeing before reuse.
Instead, non-NUMA khugepaged_prealloc_page() release the old page
if anyone else has a reference to it (1% of cases when I tested).
Although never reported on huge tmpfs, I believe its find_lock_entry()
has been at similar risk; but huge tmpfs does not rely on khugepaged
for its normal working nearly so much as READ_ONLY_THP_FOR_FS does.
Reported-by: Denis Lisov <dennis.lissov@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206569
Link: https://lore.kernel.org/linux-mm/?q=20200219144635.3b7417145de19b65f258c943%40linux-foundation.org
Reported-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/linux-xfs/?q=20200616013309.GB815%40lca.pw
Reported-and-analyzed-by: Suren Baghdasaryan <surenb@google.com>
Fixes: 87c460a0bded ("mm/khugepaged: collapse_shmem() without freezing new_page")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org # v4.9+
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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