Date: Mon, 02 Mar 2026 00:40:06 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 293536] kgdb: source code location lookup works for kernel but not for module Message-ID: <bug-293536-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=293536 Bug ID: 293536 Summary: kgdb: source code location lookup works for kernel but not for module Product: Base System Version: 16.0-CURRENT Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: cracauer@cons.org tl;dr: I have a bhyve kgdb situation, debugging a module. The source code is synced between guest and host, both located at /usr/src-debug. However, the debugger insists on using /usr/src for the module, although the correct /usr/src-debug is used for the kernel. Consider this backtrace: #0 panic (fmt=0xffffffff83012022 "No cnp") at /usr/src-debug/sys/kern/kern_shutdown.c:886 #1 0xffffffff830116a0 in sysctl_rule (oidp=<optimized out>, arg1=0x0 <ugidfw_check>, arg2=-2097078112, req=0xffffffff830120a0) at /xcarb3/usr/src/sys/security/mac_bsdextended/mac_bsdextended.c:145 #2 0xffffffff83011714 in sysctl_rule (oidp=<optimized out>, arg1=<optimized out>, arg2=<optimized out>, req=0x40 <ugidfw_check+64>) at /xcarb3/usr/src/sys/security/mac_bsdextended/mac_bsdextended.c:154 #3 0xffffffff80f3c56b in mac_vnode_check_lookup_impl ( cred=cred@entry=0xfffff8037415ed80, dvp=dvp@entry=0xfffff80001b0a1b8, cnp=0xfffffe00d5fa68f8, cnp@entry=0xfffffe00d5fa6d18) at /usr/src-debug/sys/security/mac/mac_vfs.c:576 #4 0xffffffff80cc5a7d in mac_vnode_check_lookup (cred=0xfffff8037415ed80, dvp=0xfffff80001b0a1b8, cnp=0xfffffe00d5fa6d18) at /usr/src-debug/sys/security/mac/mac_framework.h:565 #5 vfs_lookup (ndp=ndp@entry=0xfffffe00d5fa6c98) at /usr/src-debug/sys/kern/vfs_lookup.c:1311 #6 0xffffffff80cc472d in namei (ndp=ndp@entry=0xfffffe00d5fa6c98) at /usr/src-debug/sys/kern/vfs_lookup.c:738 #7 0xffffffff80cefd52 in vn_open_cred (ndp=ndp@entry=0xfffffe00d5fa6c98, flagp=flagp@entry=0xfffffe00d5fa6db4, cmode=cmode@entry=420, --Type <RET> for more, q to quit, c to continue without paging-- vn_open_flags=vn_open_flags@entry=16, cred=0xfffff8037415ed80, fp=0xfffff8000583a050) at /usr/src-debug/sys/kern/vfs_vnops.c:369 #8 0xffffffff80ce5747 in openatfp (td=0xfffff8000584b000, dirfd=dirfd@entry=-100, path=0x824cba112 "/var/run/utx.active", pathseg=pathseg@entry=UIO_USERSPACE, flags=1048577, mode=<optimized out>, fpp=0x0 <ugidfw_check>) at /usr/src-debug/sys/kern/vfs_syscalls.c:1263 #9 0xffffffff80ce5408 in kern_openat (td=0xffffffff83012022, dirfd=-100, path=0xffffffff830120a0 "FOO3: '%s'\n", pathseg=UIO_USERSPACE, flags=92581888, mode=-2111371672) at /usr/src-debug/sys/kern/vfs_syscalls.c:1351 As you can see /xcarb3/usr/src is used for the module (which is the unedited host source code). The correct /usr/src-debug is used for the kernel. Inside, kernel.debug and mac_bsdextended.ko.debug both clearly reference /usr/src-debug if you inspect the files in a hexdump. Longer story: ------------- I am bringing things into play like this: - source code is in /usr/src-debug on both guest and host - guest compiles, installs and runs the modified kernel and module - kernel.debug and mac_bsdextended.ko.debug are copied to /var/tmp on the host - invocation: kgdb /var/tmp/kernel.debug add-symbol-file /var/tmp/mac_bsdextended.ko.debug target remote localhost:1234 b panic When starting kgdb says Reading symbols from /var/tmp/kernel.debug... add symbol table from file "/var/tmp/mac_bsdextended.ko.debug" warning: remote target does not support file transfer, attempting to access file s from local filesystem. Obviously that "from local filesystem" could screw me up, but it doesn't say that it actually loads something. -- You are receiving this mail because: You are the assignee for the bug.home | help
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