Messages in this thread Patch in this message | | | From | Louis Rilling <> | Subject | [PATCH] [BUGFIX] bsdacct: Fix access to invalid filp in acct_on() | Date | Thu, 18 Jun 2009 14:46:19 +0200 |
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From: Renaud Lottiaux <renaud.lottiaux@kerlabs.com>
The file opened in acct_on and freshly stored in the ns->bacct struct can be closed in acct_file_reopen by a concurrent call after we release acct_lock and before we call mntput(file->f_path.mnt).
Record file->f_path.mnt in a local variable and use this variable only.
Signed-off-by: Renaud Lottiaux <renaud.lottiaux@kerlabs.com> Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com> --- kernel/acct.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/acct.c b/kernel/acct.c index 7afa315..9f33910 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -215,6 +215,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file, static int acct_on(char *name) { struct file *file; + struct vfsmount *mnt; int error; struct pid_namespace *ns; struct bsd_acct_struct *acct = NULL; @@ -256,11 +257,12 @@ static int acct_on(char *name) acct = NULL; } - mnt_pin(file->f_path.mnt); + mnt = file->f_path.mnt; + mnt_pin(mnt); acct_file_reopen(ns->bacct, file, ns); spin_unlock(&acct_lock); - mntput(file->f_path.mnt); /* it's pinned, now give up active reference */ + mntput(mnt); /* it's pinned, now give up active reference */ kfree(acct); return 0; -- 1.5.6.5
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