[PATCH v2 5/6] proc: Clear the pieces of proc_inode that proc_evict_inode cares about
From: Eric W. Biederman <hidden>
Date: 2020-02-24 16:31:00
Also in:
linux-fsdevel, linux-security-module, lkml
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
This just keeps everything tidier, and allows for using flags like SLAB_TYPESAFE_BY_RCU where slabs are not always cleared before reuse. I don't see reuse without reinitializing happening with the proc_inode but I had a false alarm while reworking flushing of proc dentries and indoes when a process dies that caused me to tidy this up. The code is a little easier to follow and reason about this way so I figured the changes might as well be kept. Signed-off-by: "Eric W. Biederman" <redacted> --- fs/proc/inode.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index ba6acd300ce1..d9243b24554a 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c@@ -33,21 +33,27 @@ static void proc_evict_inode(struct inode *inode) { struct proc_dir_entry *de; struct ctl_table_header *head; + struct proc_inode *ei = PROC_I(inode); truncate_inode_pages_final(&inode->i_data); clear_inode(inode); /* Stop tracking associated processes */ - put_pid(PROC_I(inode)->pid); + if (ei->pid) { + put_pid(ei->pid); + ei->pid = NULL; + } /* Let go of any associated proc directory entry */ - de = PDE(inode); - if (de) + de = ei->pde; + if (de) { pde_put(de); + ei->pde = NULL; + } - head = PROC_I(inode)->sysctl; + head = ei->sysctl; if (head) { - RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL); + RCU_INIT_POINTER(ei->sysctl, NULL); proc_sys_evict_inode(inode, head); } }
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2.25.0