Date: Sat, 24 May 2025 15:46:55 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 287049] geom: foot shooting not allowed on slice Message-ID: <bug-287049-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287049 Bug ID: 287049 Summary: geom: foot shooting not allowed on slice Product: Base System Version: Unspecified Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: d8zNeCFG@aon.at Scenario: - FreeBSD stable/14 ca. Feb. 1 - Disk setup: MBR with one slice containing a boot ZFS partition, the main ZFS partition, and a swap area: [0]# gpart show => 63 1953525105 ada0 MBR (932G) 63 1 - free - (512B) 64 1953525104 4 freebsd [active] (932G) => 0 1953525104 ada0s4 BSD (932G) 0 4194304 1 freebsd-zfs (2.0G) 4194304 4325376 2 freebsd-swap (2.1G) 8519680 1945005424 4 freebsd-zfs (927G) [0]# - Want to update the boot loader in ada0s4 to the latest /boot/zfsboot as described in zfsboot(8). This is on the running system. - The first block of ada0s4 does not need to be changed, so only the following commands are executed: - sysctl kern.geom.debugflags=0x10 - dd if=/boot/zfsboot of=/dev/ada0s4 iseek=1 oseek=1024 Result: - The dd fails with "permission denied" Expected result: - Since kern.geom.debugflags is set to 0x10, "foot shooting" should be allowed, and the command should succeed. Scenario (continued): - ada0s4 starts at block 64, so try writing via ada0 directly. - Execute the following: - dd if=/boot/zfsboot of=/dev/ada0 iseek=1 oseek=1088 Result: - This succeeds. Expected result: - Surprised that this works, when the correct way of doing this via the slice does not. -- Martin -- You are receiving this mail because: You are the assignee for the bug.home | help
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