[Bug 263662] kernel panics if fuse daemon returns parent's i-number in FUSE_CREATE
Date: Fri, 29 Apr 2022 17:52:22 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=263662 Bug ID: 263662 Summary: kernel panics if fuse daemon returns parent's i-number in FUSE_CREATE Product: Base System Version: Unspecified Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: rtm@lcs.mit.edu Attachment #233588 text/plain mime type: Created attachment 233588 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=233588&action=edit fuse daemon that causes a panic by returning parent dir's i-number for FUSE_CREATE If a fuse daemon returns the parent directory's i-number for a new file in FUSE_CREATE, the kernel notices that it is trying to acquire a lock it already holds, and panics. I've attached a demo: # uname -a FreeBSD 14.0-CURRENT FreeBSD 14.0-CURRENT #1 main-n250917-440e36e68279: Fri Apr 29 07:33:58 EDT 2022 rtm@xxx:/usr/obj/usr/rtm/symbsd/src/riscv.riscv64/sys/RTM2 riscv # pkg install fusefs-libs # cc -I/usr/local/include/fuse -o futo1a futo1a.c -L/usr/local/lib -lfuse # ./futo1a ... panic: lockmgr_xlock_hard: recursing on non recursive lockmgr 0xffffffd0012e5cb0 @ /usr/rtm/symbsd/src/sys/kern/vfs_subr.c:3023 cpuid = 0 time = 1649872295 KDB: stack backtrace: db_trace_self() at db_trace_self db_trace_self_wrapper() at db_trace_self_wrapper+0x38 kdb_backtrace() at kdb_backtrace+0x2c vpanic() at vpanic+0x16e panic() at panic+0x2a lockmgr_xlock_hard() at lockmgr_xlock_hard+0xb4 lockmgr_lock_flags() at lockmgr_lock_flags+0x14e vop_stdlock() at vop_stdlock+0x1c VOP_LOCK1_APV() at VOP_LOCK1_APV+0x32 VOP_LOCK1() at VOP_LOCK1+0x2e _vn_lock() at _vn_lock+0x30 vget_finish() at vget_finish+0x48 vfs_hash_get() at vfs_hash_get+0xb6 fuse_vnode_alloc() at fuse_vnode_alloc+0x5c fuse_vnode_get() at fuse_vnode_get+0x48 fuse_vnop_create() at fuse_vnop_create+0x300 VOP_CREATE_APV() at VOP_CREATE_APV+0x3a VOP_CREATE() at VOP_CREATE+0x2e vn_open_cred() at vn_open_cred+0x21e kern_openat() at kern_openat+0x16a sys_openat() at sys_openat+0x32 syscallenter() at syscallenter+0xf4 ecall_handler() at ecall_handler+0x18 do_trap_user() at do_trap_user+0xea cpu_exception_handler_user() at cpu_exception_handler_user+0x72 --- exception 8, tval = 0xd12b67000 KDB: enter: panic [ thread pid 35 tid 100051 ] Stopped at breakpoint+0xa: c.ldsp s0,0(sp) db> -- You are receiving this mail because: You are the assignee for the bug.