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KCSAN: data-race in meminfo_proc_show / percpu_counter_add_batch

Status: auto-closed as invalid on 2020/05/04 01:44
Subsystems: lsm
[Documentation on labels]
First crash: 1548d, last: 1523d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in meminfo_proc_show / percpu_counter_add_batch

write to 0xffffffff86238108 of 8 bytes by task 8011 on cpu 0:
 percpu_counter_add_batch+0xca/0x150 lib/percpu_counter.c:91
 vm_acct_memory include/linux/mman.h:68 [inline]
 __vm_enough_memory+0x56/0x210 mm/util.c:805
 security_vm_enough_memory_mm+0x94/0xb0 security/security.c:804
 dup_mmap kernel/fork.c:546 [inline]
 dup_mm+0x310/0xba0 kernel/fork.c:1366
 copy_mm kernel/fork.c:1422 [inline]
 copy_process+0x39d7/0x3b40 kernel/fork.c:2087
 _do_fork+0xfe/0x7a0 kernel/fork.c:2436
 __do_sys_clone kernel/fork.c:2591 [inline]
 __se_sys_clone kernel/fork.c:2572 [inline]
 __x64_sys_clone+0x130/0x170 kernel/fork.c:2572
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff86238108 of 8 bytes by task 8383 on cpu 1:
 meminfo_proc_show+0x58/0x870 fs/proc/meminfo.c:45
 seq_read+0x350/0x9d0 fs/seq_file.c:229
 proc_reg_read+0xe9/0x140 fs/proc/inode.c:223
 do_loop_readv_writev fs/read_write.c:714 [inline]
 do_loop_readv_writev fs/read_write.c:701 [inline]
 do_iter_read+0x357/0x3d0 fs/read_write.c:935
 vfs_readv+0x9c/0xf0 fs/read_write.c:1053
 do_preadv+0x131/0x1d0 fs/read_write.c:1145
 __do_sys_preadv fs/read_write.c:1195 [inline]
 __se_sys_preadv fs/read_write.c:1190 [inline]
 __x64_sys_preadv+0x61/0x80 fs/read_write.c:1190
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8383 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/02/24 01:43 https://github.com/google/ktsan.git kcsan 766d004d1b85 d801cb02 .config console log report ci2-upstream-kcsan-gce
2020/01/29 13:40 https://github.com/google/ktsan.git kcsan 245a43005292 c8e81ce4 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.