I suspect the easiest way here is just to check that your credential in args[6] is non-null in a predicate.
- Samuel Lepetit - [email protected] <mailto:[email protected]> > On 18 May 2017, at 13:20, Andreas Longwitz <[email protected]> wrote: > > Now running FreeBSD 10.3-STABLE #0 r317936 I try to understand the > problem described in > > https://lists.freebsd.org/pipermail/freebsd-fs/2013-November/018610.html > > using DTrace. Therefore I like to use the probe > > fbt:kernel:breadn_flags:entry > > to see what is happening in ffs_vgetf() in source ffs_vfsops.c: > > #define bread(vp, blkno, size, cred, bpp) \ > breadn_flags(vp, blkno, size, NULL, NULL, 0, cred, 0, bpp) > > /* Read in the disk contents for the inode, copy into the inode. */ > error = bread(ump->um_devvp, fsbtodb(fs, ino_to_fsba(fs, ino)), > (int)fs->fs_bsize, NOCRED, &bp); > > I get the error > > dtrace: error on enabled probe ID 22 (ID 31371: > fbt:kernel:breadn_flags:entry): invalid address (0x0) in action #6 > > probably because NOCRED is NULL: > > #define NOCRED ((struct ucred *)0) > > I like to know if this case can be handled in DTrace, the parameter > > args[6]: struct ucred * > > is sometimes a pointer and sometimes NOCRED. > > > -- > Dr. Andreas Longwitz > > _______________________________________________ > [email protected] mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-dtrace > To unsubscribe, send any mail to "[email protected]" _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-dtrace To unsubscribe, send any mail to "[email protected]"
