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From: syzbot <syzbot+c034966b0b02f94f7f34@syzkaller.appspotmail.com>
To: aarcange@redhat.com, akpm@linux-foundation.org,
	christian@brauner.io, cyphar@cyphar.com,
	elena.reshetova@intel.com, elver@google.com, guro@fb.com,
	keescook@chromium.org, ldv@altlinux.org,
	linux-kernel@vger.kernel.org, luto@amacapital.net,
	mhocko@suse.com, mingo@kernel.org, peterz@infradead.org,
	syzkaller-bugs@googlegroups.com, tglx@linutronix.de,
	viro@zeniv.linux.org.uk, wad@chromium.org
Subject: KCSAN: data-race in __rb_rotate_set_parents / vm_area_dup
Date: Thu, 24 Oct 2019 09:07:08 -0700	[thread overview]
Message-ID: <000000000000b49e190595aa39fe@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    05f22368 x86, kcsan: Enable KCSAN for x86
git tree:       https://github.com/google/ktsan.git kcsan
console output: https://syzkaller.appspot.com/x/log.txt?x=1060c47b600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=87d111955f40591f
dashboard link: https://syzkaller.appspot.com/bug?extid=c034966b0b02f94f7f34
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c034966b0b02f94f7f34@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __rb_rotate_set_parents / vm_area_dup

read to 0xffff88811eef53e8 of 200 bytes by task 7738 on cpu 0:
  vm_area_dup+0x70/0xf0 kernel/fork.c:359
  __split_vma+0x88/0x350 mm/mmap.c:2678
  __do_munmap+0xb02/0xb60 mm/mmap.c:2803
  do_munmap mm/mmap.c:2856 [inline]
  mmap_region+0x165/0xd50 mm/mmap.c:1749
  do_mmap+0x6d4/0xba0 mm/mmap.c:1577
  do_mmap_pgoff include/linux/mm.h:2353 [inline]
  vm_mmap_pgoff+0x12d/0x190 mm/util.c:496
  ksys_mmap_pgoff+0x2d8/0x420 mm/mmap.c:1629
  __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
  __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
  __x64_sys_mmap+0x91/0xc0 arch/x86/kernel/sys_x86_64.c:91
  do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88811eef5440 of 8 bytes by task 7737 on cpu 1:
  __rb_rotate_set_parents+0x4d/0xf0 lib/rbtree.c:79
  __rb_insert lib/rbtree.c:215 [inline]
  __rb_insert_augmented+0x109/0x370 lib/rbtree.c:459
  rb_insert_augmented include/linux/rbtree_augmented.h:50 [inline]
  rb_insert_augmented_cached include/linux/rbtree_augmented.h:60 [inline]
  vma_interval_tree_insert+0x196/0x230 mm/interval_tree.c:23
  __vma_link_file+0xd9/0x110 mm/mmap.c:634
  __vma_adjust+0x1ac/0x12a0 mm/mmap.c:842
  vma_adjust include/linux/mm.h:2276 [inline]
  __split_vma+0x208/0x350 mm/mmap.c:2707
  split_vma+0x73/0xa0 mm/mmap.c:2736
  mprotect_fixup+0x43f/0x510 mm/mprotect.c:413
  do_mprotect_pkey+0x3eb/0x660 mm/mprotect.c:553
  __do_sys_mprotect mm/mprotect.c:578 [inline]
  __se_sys_mprotect mm/mprotect.c:575 [inline]
  __x64_sys_mprotect+0x51/0x70 mm/mprotect.c:575
  do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7737 Comm: blkid Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

             reply	other threads:[~2019-10-24 16:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24 16:07 syzbot [this message]
2019-10-24 16:24 ` Peter Zijlstra
2019-10-24 18:59   ` Marco Elver
2019-10-25  9:01     ` Peter Zijlstra
2019-10-25 17:35       ` Marco Elver

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