[Valgrind-developers] [valgrind] Avoid dev/inode check on btrfs with --sanity-level=3

[Paul F. <pa...@so...>]

https://sourceware.org/git/gitweb.cgi?p=valgrind.git;h=3b06d458ffc5cc8de8d701926e5d86979185fa04

commit 3b06d458ffc5cc8de8d701926e5d86979185fa04
Author: Mark Wielaard <ma...@kl...>
Date:   Thu Jul 4 15:21:39 2024 +0200

    Avoid dev/inode check on btrfs with --sanity-level=3
    
    With --sanity-level=3 or higher the aspacemgr sanity checks the
    device/inode numbers from /proc/self/maps to the file stat
    results. These don't match on btrfs. So detect when a file is on a
    btrfs volume and ignore the check in that case.
    
    https://bugs.kde.org/show_bug.cgi?id=317127

Diff:
---
 NEWS                                    |  1 +
 coregrind/m_aspacemgr/aspacemgr-linux.c | 13 +++++++++++++
 include/vki/vki-linux.h                 |  6 ++++++
 3 files changed, 20 insertions(+)

diff --git a/NEWS b/NEWS
index 87aa1bd7dd..dde8713d60 100644
--- a/NEWS
+++ b/NEWS
@@ -31,6 +31,7 @@ are not entered into bugzilla tend to get forgotten about or ignored.
         valgrind: vex x86->IR: unhandled instruction bytes:
         0x66 0xF 0x3A 0x2
 311655  --log-file=FILE leads to apparent fd leak
+317127  Fedora18/x86_64 --sanity-level=3 : aspacem segment mismatch
 337388  fcntl works on Valgrind's own file descriptors
 377966  arm64 unhandled instruction dc zva392146  aarch64: unhandled
         instruction 0xD5380001 (MRS rT, midr_el1)
diff --git a/coregrind/m_aspacemgr/aspacemgr-linux.c b/coregrind/m_aspacemgr/aspacemgr-linux.c
index 9362f65af3..bae4f781a8 100644
--- a/coregrind/m_aspacemgr/aspacemgr-linux.c
+++ b/coregrind/m_aspacemgr/aspacemgr-linux.c
@@ -891,6 +891,19 @@ static void sync_check_mapping_callback ( Addr addr, SizeT len, UInt prot,
       /* hack apparently needed on MontaVista Linux */
       if (filename && VG_(strstr)(filename, "/.lib-ro/"))
          cmp_devino = False;
+
+      /* On linux systems we want to avoid dev/inode check on btrfs,
+         we can use the statfs call for that, except on nanomips
+         (which also doesn't have a sys_fstatfs syswrap).
+         See https://bugs.kde.org/show_bug.cgi?id=317127 */
+#if !defined(VGP_nanomips_linux)
+      struct vki_statfs statfs = {0};
+      SysRes res = VG_(do_syscall2)(__NR_statfs, (UWord)filename,
+                                    (UWord)&statfs);
+      if (!sr_isError(res) && statfs.f_type == VKI_BTRFS_SUPER_MAGIC) {
+         cmp_devino = False;
+      }
+#endif
 #endif
       
       /* If we are doing sloppy execute permission checks then we
diff --git a/include/vki/vki-linux.h b/include/vki/vki-linux.h
index be3d76690c..ccdb808af7 100644
--- a/include/vki/vki-linux.h
+++ b/include/vki/vki-linux.h
@@ -5455,6 +5455,12 @@ struct vki_open_how {
 #define VKI_CLOSE_RANGE_UNSHARE (1U << 1)
 #define VKI_CLOSE_RANGE_CLOEXEC (1U << 2)
 
+//----------------------------------------------------------------------
+// From linux/magic.h
+//----------------------------------------------------------------------
+
+#define VKI_BTRFS_SUPER_MAGIC    0x9123683E
+
 /*--------------------------------------------------------------------*/
 /*--- end                                                          ---*/
 /*--------------------------------------------------------------------*/