Date: Sun, 29 Mar 2026 16:16:48 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 294120] virtio_blk: cannot dump core after c8c37141a661cc9a6a51e43599d1afc8a3f0ef46 Message-ID: <bug-294120-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294120 Bug ID: 294120 Summary: virtio_blk: cannot dump core after c8c37141a661cc9a6a51e43599d1afc8a3f0ef46 Product: Base System Version: 16.0-CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: asomers@FreeBSD.org It is no longer possible for me to write a core dump in my VM using a virtio-blk disk. When I try, I get an error like the below. I've narrowed the breakage down to one commit https://github.com/freebsd/freebsd-src/commit/c8c37141a661cc9a6a51e43599d1afc8a3f0ef46 . Steps to Reproduce ================== 1) Create a FreeBSD 16.0-CURRENT x86_64 BHyve VM with a virtio-blk disk and configure it as a dump device. 2) trigger a panic, with sudo sysctl debug.kdb.panic=1 3) On the serial console, type "dump" Console Output ============== login: panic: kdb_sysctl_panic cpuid = 5 time = 1774797651 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00d92eba20 vpanic() at vpanic+0x136/frame 0xfffffe00d92ebb50 panic() at panic+0x43/frame 0xfffffe00d92ebbb0 kdb_sysctl_panic() at kdb_sysctl_panic+0x63/frame 0xfffffe00d92ebbe0 sysctl_root_handler_locked() at sysctl_root_handler_locked+0x9c/frame 0xfffffe00d92ebc30 sysctl_root() at sysctl_root+0x22f/frame 0xfffffe00d92ebcb0 userland_sysctl() at userland_sysctl+0x1b6/frame 0xfffffe00d92ebd50 sys___sysctl() at sys___sysctl+0x65/frame 0xfffffe00d92ebe00 amd64_syscall() at amd64_syscall+0x1c4/frame 0xfffffe00d92ebf30 fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe00d92ebf30 --- syscall (202, FreeBSD ELF64, __sysctl), rip = 0x3c4f12192b8a, rsp = 0x3c4f1115f7c8, rbp = 0x3c4f1115f810 --- KDB: enter: panic [ thread pid 4883 tid 100251 ] Stopped at kdb_enter+0x33: movq $0,0x15f6322(%rip) db> dump Dumping 675 out of 16343 MB:KDB: reentering KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00d92eb020 kdb_reenter() at kdb_reenter+0x2b/frame 0xfffffe00d92eb030 calltrap() at calltrap+0x8/frame 0xfffffe00d92eb030 --- trap 0xc, rip = 0xffffffff809ee1f6, rsp = 0xfffffe00d92eb100, rbp = 0xfffffe00d92eb2e0 --- vtblk_dump() at vtblk_dump+0xa6/frame 0xfffffe00d92eb2e0 _dump_append() at _dump_append+0x154/frame 0xfffffe00d92eb350 blk_write() at blk_write+0x156/frame 0xfffffe00d92eb3a0 cpu_minidumpsys() at cpu_minidumpsys+0x92b/frame 0xfffffe00d92eb450 dumpsys_generic() at dumpsys_generic+0x5a/frame 0xfffffe00d92eb530 doadump() at doadump+0x88/frame 0xfffffe00d92eb550 db_dump() at db_dump+0x2a/frame 0xfffffe00d92eb570 db_command() at db_command+0x30d/frame 0xfffffe00d92eb630 db_command_loop() at db_command_loop+0x4d/frame 0xfffffe00d92eb640 db_trap() at db_trap+0xe6/frame 0xfffffe00d92eb6d0 kdb_trap() at kdb_trap+0x24f/frame 0xfffffe00d92eb820 trap() at trap+0x79d/frame 0xfffffe00d92eb950 calltrap() at calltrap+0x8/frame 0xfffffe00d92eb950 --- trap 0x3, rip = 0xffffffff80c29d63, rsp = 0xfffffe00d92eba28, rbp = 0xfffffe00d92ebb50 --- kdb_enter() at kdb_enter+0x33/frame 0xfffffe00d92ebb50 panic() at panic+0x43/frame 0xfffffe00d92ebbb0 -- You are receiving this mail because: You are the assignee for the bug.home | help
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