Date: Sat, 29 Oct 2011 15:34:40 -0700 From: Kirk McKusick <mckusick@mckusick.com> To: "deeptech71@gmail.com" <deeptech71@gmail.com> Cc: freebsd-current@freebsd.org Subject: Re: panic: ffs_blkfree_cg: freeing free block Message-ID: <201110292234.p9TMYeSU047757@chez.mckusick.com> In-Reply-To: <CAF6hryRK6KQsm6Rj90Ytv8xV1fZzPFAC46WV3nWihJgteVPwuQ@mail.gmail.com>
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> Date: Fri, 28 Oct 2011 11:16:59 +0200 > From: "deeptech71@gmail.com" <deeptech71@gmail.com> > To: freebsd-current@freebsd.org > Subject: panic: ffs_blkfree_cg: freeing free block > > A panic occured while I was ``rm -rf''ing a large file&directory tree > (that I just created with untar) on an old drive that I have not used > for a long time. Unfortunately I'm not 100% sure that the filesystem > was clean when I mounted it today. Could that result in such a panic? > > I don't have the intermediate object files for the kernel; now I'm > building the kernel again (from the appropriate, exact sources). That > shouldn't harm debugging, should it? Meanwhile, I'll take any debug > info requests, which I'll attempt to address shortly. This panic happens when the free-block bitmap is corrupted. That can happen due to: 1) An unclean filesystem being mounted (though you should get a warning when you attempt to do this). 2) Bit-rot on the disk that is not checked for before mounting. This is typically only an issue for a disk that has been offline for a long time. 3) Write errors to the disk. There have been no changes to the code that manage the filesystem bitmaps in decades (nearly three decades), so a software cause of this panic is unlikely to have been recently introduced. Hence, I would not spend a lot of time trying to get a backtrace, etc. Kirk McKusick
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