The patch titled bsd_acct: plain current->real_parent access is not always safe has been added to the -mm tree. Its filename is bsd_acct-plain-current-real_parent-access-is-not-always-safe.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: bsd_acct: plain current->real_parent access is not always safe From: Pavel Emelyanov <xemul@xxxxxxxxxx> This is minor, but dereferencing even current real_parent is not safe on debug kernels, since the memory, this points to, can be unmapped - RCU protection is required. Besides, the tgid field is deprecated and is to be replaced with task_tgid_xxx call (the 2nd patch), so RCU will be required anyway. Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/acct.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff -puN kernel/acct.c~bsd_acct-plain-current-real_parent-access-is-not-always-safe kernel/acct.c --- a/kernel/acct.c~bsd_acct-plain-current-real_parent-access-is-not-always-safe +++ a/kernel/acct.c @@ -482,7 +482,9 @@ static void do_acct_process(struct file #endif #if ACCT_VERSION==3 ac.ac_pid = current->tgid; - ac.ac_ppid = current->real_parent->tgid; + rcu_read_lock(); + ac.ac_ppid = rcu_dereference(current->real_parent)->tgid; + rcu_read_unlock(); #endif spin_lock_irq(¤t->sighand->siglock); _ Patches currently in -mm which might be from xemul@xxxxxxxxxx are memcgroup-fix-check-for-thread-being-a-group-leader-in-memcgroup.patch git-kgdb-light.patch use-find_task_by_vpid-in-audit-code.patch ia64-fix-getpid-and-set_tid_address-fast-system-calls-for-pid-namespaces.patch git-udf.patch bsd_acct-plain-current-real_parent-access-is-not-always-safe.patch bsd_acct-using-task_struct-tgid-is-not-right-in-pid-namespaces.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx-fix-memcg-ooms.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx-just-return-do_try_to_free_pages.patch mm-have-zonelist-contains-structs-with-both-a-zone-pointer-and-zone_idx-just-return-do_try_to_free_pages-do_try_to_free_pages-gfp_mask-redundant.patch binfmt_miscc-avoid-potential-kernel-stack-overflow.patch cgroup-api-files-rename-read-write_uint-methods-to-read_write_u64.patch cgroup-api-files-add-res_counter_read_u64.patch cgroup-api-files-use-read_u64-in-memory-controller.patch cgroup-api-files-strip-all-trailing-whitespace-in-cgroup_write_u64.patch cgroup-api-files-update-cpusets-to-use-cgroup-structured-file-api.patch cgroup-api-files-update-cpusets-to-use-cgroup-structured-file-api-fix.patch cgroup-api-files-add-cgroup-map-data-type.patch cgroup-api-files-use-cgroup-map-for-memcontrol-stats-file.patch cgroup-api-files-drop-mem_cgroup_force_empty.patch cgroup-api-files-move-releasable-to-cgroup_debug-subsystem.patch cgroup-api-files-make-cgroup_debug-default-to-off.patch cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time.patch cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time-fix-boot-option-parsing.patch cgroups-add-the-trigger-callback-to-struct-cftype.patch memory-controller-make-memory-resource-control-aware-of-boot-options.patch memcgroup-add-the-max_usage-member-on-the-res_counter.patch add-a-document-describing-the-resource-counter-abstraction-v2.patch add-a-document-describing-the-resource-counter-abstraction-v2-fix.patch memcgroup-move-memory-controller-allocations-to-their-own-slabs.patch memcgroup-use-triggers-in-force_empty-and-max_usage-files.patch memcgroup-implement-failcounter-reset.patch memcgroup-implement-failcounter-reset-checkpatch-fixes.patch remove-unused-variable-from-send_signal.patch turn-legacy_queue-macro-into-static-inline-function.patch consolidate-checking-for-ignored-legacy-signals.patch consolidate-checking-for-ignored-legacy-signals-simplify.patch signals-consolidate-checks-for-whether-or-not-to-ignore-a-signal.patch signals-clean-dequeue_signal-from-excess-checks-and-assignments.patch signals-consolidate-send_sigqueue-and-send_group_sigqueue.patch signals-cleanup-security_task_kill-usage-implementation.patch signals-use-__group_complete_signal-for-the-specific-signals-too.patch signals-fold-complete_signal-into-send_signal-do_send_sigqueue.patch signals-unify-send_sigqueue-send_group_sigqueue-completely.patch sysctl-merge-equal-proc_sys_read-and-proc_sys_write.patch sysctl-clean-from-unneeded-extern-and-forward-declarations.patch sysctl-add-the-permissions-callback-on-the-ctl_table_root.patch free_pidmap-turn-it-into-free_pidmapstruct-upid.patch use-find_task_by_vpid-in-taskstats.patch deprecate-find_task_by_pid.patch deprecate-find_task_by_pid-warning-fix.patch pidns-make-pid-level-and-pid_ns-level-unsigned.patch reiser4.patch put_pid-make-sure-we-dont-free-the-live-pid.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html