Eric Lee / linux-smarc-t335x-v3.2

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Commit 3b34fc5880a2dcc7e5ed9837ef8d6bae051ab266

Authored by Oleg Nesterov
Committed by Linus Torvalds
1 parent 72a1de39f8
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

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>

Showing 2 changed files with 12 additions and 4 deletions Side-by-side Diff

... ... @@ -1340,8 +1340,10 @@
1340 1340 prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1341 1341 prstatus->pr_sigpend = p->pending.signal.sig[0];
1342 1342 prstatus->pr_sighold = p->blocked.sig[0];
  1343 + rcu_read_lock();
  1344 + prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
  1345 + rcu_read_unlock();
1343 1346 prstatus->pr_pid = task_pid_vnr(p);
1344   - prstatus->pr_ppid = task_pid_vnr(p->real_parent);
1345 1347 prstatus->pr_pgrp = task_pgrp_vnr(p);
1346 1348 prstatus->pr_sid = task_session_vnr(p);
1347 1349 if (thread_group_leader(p)) {
1348 1350  
... ... @@ -1382,8 +1384,10 @@
1382 1384 psinfo->pr_psargs[i] = ' ';
1383 1385 psinfo->pr_psargs[len] = 0;
1384 1386  
  1387 + rcu_read_lock();
  1388 + psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
  1389 + rcu_read_unlock();
1385 1390 psinfo->pr_pid = task_pid_vnr(p);
1386   - psinfo->pr_ppid = task_pid_vnr(p->real_parent);
1387 1391 psinfo->pr_pgrp = task_pgrp_vnr(p);
1388 1392 psinfo->pr_sid = task_session_vnr(p);
1389 1393  
fs/binfmt_elf_fdpic.c
Diff comments   View file @ 3b34fc5
... ... @@ -1387,8 +1387,10 @@
1387 1387 prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1388 1388 prstatus->pr_sigpend = p->pending.signal.sig[0];
1389 1389 prstatus->pr_sighold = p->blocked.sig[0];
  1390 + rcu_read_lock();
  1391 + prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
  1392 + rcu_read_unlock();
1390 1393 prstatus->pr_pid = task_pid_vnr(p);
1391   - prstatus->pr_ppid = task_pid_vnr(p->real_parent);
1392 1394 prstatus->pr_pgrp = task_pgrp_vnr(p);
1393 1395 prstatus->pr_sid = task_session_vnr(p);
1394 1396 if (thread_group_leader(p)) {
1395 1397  
... ... @@ -1432,8 +1434,10 @@
1432 1434 psinfo->pr_psargs[i] = ' ';
1433 1435 psinfo->pr_psargs[len] = 0;
1434 1436  
  1437 + rcu_read_lock();
  1438 + psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
  1439 + rcu_read_unlock();
1435 1440 psinfo->pr_pid = task_pid_vnr(p);
1436   - psinfo->pr_ppid = task_pid_vnr(p->real_parent);
1437 1441 psinfo->pr_pgrp = task_pgrp_vnr(p);
1438 1442 psinfo->pr_sid = task_session_vnr(p);
1439 1443