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authorOleg Nesterov <oleg@redhat.com>2009-06-17 16:27:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-18 13:03:52 -0700
commit3b34fc5880a2dcc7e5ed9837ef8d6bae051ab266 (patch)
tree477b9a29135cc7b8815ce7ce19201bce371c56a1 /fs
parent72a1de39f89325a834a8c70b2a0d8f71d919f640 (diff)
downloadlinux-3b34fc5880a2dcc7e5ed9837ef8d6bae051ab266.tar.gz
elf_core_dump: use rcu_read_lock() to access ->real_parent
In theory it is not safe to dereference ->parent/real_parent without tasklist or rcu lock, we can race with re-parenting. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/binfmt_elf.c8
-rw-r--r--fs/binfmt_elf_fdpic.c8
2 files changed, 12 insertions, 4 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 40381df3486..9fa212b014a 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1340,8 +1340,10 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
prstatus->pr_sigpend = p->pending.signal.sig[0];
prstatus->pr_sighold = p->blocked.sig[0];
+ rcu_read_lock();
+ prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+ rcu_read_unlock();
prstatus->pr_pid = task_pid_vnr(p);
- prstatus->pr_ppid = task_pid_vnr(p->real_parent);
prstatus->pr_pgrp = task_pgrp_vnr(p);
prstatus->pr_sid = task_session_vnr(p);
if (thread_group_leader(p)) {
@@ -1382,8 +1384,10 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
psinfo->pr_psargs[i] = ' ';
psinfo->pr_psargs[len] = 0;
+ rcu_read_lock();
+ psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+ rcu_read_unlock();
psinfo->pr_pid = task_pid_vnr(p);
- psinfo->pr_ppid = task_pid_vnr(p->real_parent);
psinfo->pr_pgrp = task_pgrp_vnr(p);
psinfo->pr_sid = task_session_vnr(p);
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index fdb66faa24f..20fbeced472 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1387,8 +1387,10 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
prstatus->pr_sigpend = p->pending.signal.sig[0];
prstatus->pr_sighold = p->blocked.sig[0];
+ rcu_read_lock();
+ prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+ rcu_read_unlock();
prstatus->pr_pid = task_pid_vnr(p);
- prstatus->pr_ppid = task_pid_vnr(p->real_parent);
prstatus->pr_pgrp = task_pgrp_vnr(p);
prstatus->pr_sid = task_session_vnr(p);
if (thread_group_leader(p)) {
@@ -1432,8 +1434,10 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
psinfo->pr_psargs[i] = ' ';
psinfo->pr_psargs[len] = 0;
+ rcu_read_lock();
+ psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+ rcu_read_unlock();
psinfo->pr_pid = task_pid_vnr(p);
- psinfo->pr_ppid = task_pid_vnr(p->real_parent);
psinfo->pr_pgrp = task_pgrp_vnr(p);
psinfo->pr_sid = task_session_vnr(p);