From: Martin Pieuchot Subject: Unlock stat(2) & co To: tech@openbsd.org Date: Mon, 6 Jan 2025 10:10:36 +0100 Diff below pushes the kernel lock around namei() and vn_stat(). ok? Index: kern/syscalls.master =================================================================== RCS file: /cvs/src/sys/kern/syscalls.master,v diff -u -p -r1.266 syscalls.master --- kern/syscalls.master 6 Jan 2025 08:57:23 -0000 1.266 +++ kern/syscalls.master 6 Jan 2025 09:06:01 -0000 @@ -104,11 +104,11 @@ 35 STD { int sys_fchflags(int fd, u_int flags); } 36 STD { void sys_sync(void); } 37 OBSOL msyscall -38 STD { int sys_stat(const char *path, struct stat *ub); } +38 STD NOLOCK { int sys_stat(const char *path, struct stat *ub); } 39 STD NOLOCK { pid_t sys_getppid(void); } -40 STD { int sys_lstat(const char *path, struct stat *ub); } +40 STD NOLOCK { int sys_lstat(const char *path, struct stat *ub); } 41 STD NOLOCK { int sys_dup(int fd); } -42 STD { int sys_fstatat(int fd, const char *path, \ +42 STD NOLOCK { int sys_fstatat(int fd, const char *path, \ struct stat *buf, int flag); } 43 STD NOLOCK { gid_t sys_getegid(void); } 44 STD { int sys_profil(caddr_t samples, size_t size, \ Index: kern/vfs_syscalls.c =================================================================== RCS file: /cvs/src/sys/kern/vfs_syscalls.c,v diff -u -p -r1.370 vfs_syscalls.c --- kern/vfs_syscalls.c 5 Nov 2024 06:03:19 -0000 1.370 +++ kern/vfs_syscalls.c 6 Jan 2025 09:06:02 -0000 @@ -2066,10 +2066,14 @@ dofstatat(struct proc *p, int fd, const NDINITAT(&nd, LOOKUP, follow | LOCKLEAF, UIO_USERSPACE, fd, path, p); nd.ni_pledge = PLEDGE_RPATH; nd.ni_unveil = UNVEIL_READ; - if ((error = namei(&nd)) != 0) + KERNEL_LOCK(); + if ((error = namei(&nd)) != 0) { + KERNEL_UNLOCK(); return (error); + } error = vn_stat(nd.ni_vp, &sb, p); vput(nd.ni_vp); + KERNEL_UNLOCK(); if (error) return (error); /* Don't let non-root see generation numbers (for NFS security) */