lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Mon, 18 Nov 2019 20:41:40 +0000
Subject: [Bug 205569] New: potential data race (likely benign) on
 inode->i_state (reading and writing to different bits)

            Bug ID: 205569
           Summary: potential data race (likely benign) on inode->i_state
                    (reading and writing to different bits)
           Product: File System
           Version: 2.5
    Kernel Version: 5.4-rc5
          Hardware: All
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: ext4
        Regression: No

I am reporting a potential data race (maybe benign) in the ext4 layer on
inode->i_state, with reading and writing to the same byte but different bits:
I_DIRTY_PAGES (bit 2) and I_NEW | I_FREEING (bit 3 and 5), observable during
the write-back phase.

The function call trace is shown below:

[Thread 1: SYS_rmdir]
          [READ] WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&

[Thread 2: write-back thread]
            [WRITE] dirty = inode->i_state & I_DIRTY;

I could confirm that the WRITE may happen before and after the READ operation
by controlling the timing of the two threads, i.e., by setting breakpoints
before the WRITE statement.

However, I am not very sure about the implication of such a data race (e.g.,
causing violations of assumptions). I would appreciate if you could help check
on this potential bug and advise whether this is a harmful data race or it
is intended. Thank you!

You are receiving this mail because:
You are watching the assignee of the bug.

Powered by blists - more mailing lists