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Chunwei Chen
c79d5e4f33
On Linux, when doing path lookup with LOOKUP_RCU, dentry and inode can be dereferenced without refcounts and locks. For this reason, dentry and inode must only be freed after RCU grace period. However, zfs currently frees inode in zfs_inode_destroy synchronously and we can't use GPL-only call_rcu() in zfs directly. Fortunately, on Linux 5.2 and after, if we define sops->free_inode(), the kernel will do call_rcu() for us. This issue may be triggered more easily with init_on_free=1 boot parameter: BUG: kernel NULL pointer dereference, address: 0000000000000020 RIP: 0010:selinux_inode_permission+0x10e/0x1c0 Call Trace: ? show_trace_log_lvl+0x1be/0x2d9 ? show_trace_log_lvl+0x1be/0x2d9 ? show_trace_log_lvl+0x1be/0x2d9 ? security_inode_permission+0x37/0x60 ? __die_body.cold+0x8/0xd ? no_context+0x113/0x220 ? exc_page_fault+0x6d/0x130 ? asm_exc_page_fault+0x1e/0x30 ? selinux_inode_permission+0x10e/0x1c0 security_inode_permission+0x37/0x60 link_path_walk.part.0.constprop.0+0xb5/0x360 ? path_init+0x27d/0x3c0 path_lookupat+0x3e/0x1a0 filename_lookup+0xc0/0x1d0 ? __check_object_size.part.0+0x123/0x150 ? strncpy_from_user+0x4e/0x130 ? getname_flags.part.0+0x4b/0x1c0 vfs_statx+0x72/0x120 ? ioctl_has_perm.constprop.0.isra.0+0xbd/0x120 __do_sys_newlstat+0x39/0x70 ? __x64_sys_ioctl+0x8d/0xd0 do_syscall_64+0x30/0x40 entry_SYSCALL_64_after_hwframe+0x62/0xc7 Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Rob Norris <rob.norris@klarasystems.com> Signed-off-by: Chunwei Chen <david.chen@nutanix.com> Co-authored-by: Chunwei Chen <david.chen@nutanix.com> Closes #17546
OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.
Official Resources
- Documentation - for using and developing this repo
- ZoL Site - Linux release info & links
- Mailing lists
- OpenZFS site - for conference videos and info on other platforms (illumos, OSX, Windows, etc)
Installation
Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.
Contribute & Develop
We have a separate document with contribution guidelines.
We have a Code of Conduct.
Release
OpenZFS is released under a CDDL license.
For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197
Supported Kernels
- The
METAfile contains the officially recognized supported Linux kernel versions. - Supported FreeBSD versions are any supported branches and releases starting from 13.0-RELEASE.