Date: Thu, 18 May 2017 22:20:05 +0200 From: Andreas Longwitz <longwitz@incore.de> To: freebsd-dtrace@freebsd.org Subject: fbt:kernel:breadn_flags:entry): invalid address (0x0) in action #7 Message-ID: <591E01F5.8080208@incore.de>
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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
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