linux/kernel
Vivek Goyal 800df627e2 resource: fix the case of null pointer access
Richard and Daniel reported that UML is broken due to changes to
resource traversal functions.  Problem is that iomem_resource.child can
be null and new code does not consider that possibility.  Old code used
a for loop and that loop will not even execute if p was null.

Revert back to for() loop logic and bail out if p is null.

I also moved sibling_only check out of resource_lock. There is no
reason to keep it inside the lock.

Following is backtrace of the UML crash.

RIP: 0033:[<0000000060039b9f>]
RSP: 0000000081459da0  EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00000000219b3fff RCX: 000000006010d1d9
RDX: 0000000000000001 RSI: 00000000602dfb94 RDI: 0000000081459df8
RBP: 0000000081459de0 R08: 00000000601b59f4 R09: ffffffff0000ff00
R10: ffffffff0000ff00 R11: 0000000081459e88 R12: 0000000081459df8
R13: 00000000219b3fff R14: 00000000602dfb94 R15: 0000000000000000
Kernel panic - not syncing: Segfault with no mm
CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-10454-g58d08e3 #13
Stack:
 00000000 000080d0 81459df0 219b3fff
 81459e70 6010d1d9 ffffffff 6033e010
 81459e50 6003a269 81459e30 00000000
Call Trace:
 [<6010d1d9>] ? kclist_add_private+0x0/0xe7
 [<6003a269>] walk_system_ram_range+0x61/0xb7
 [<6000e859>] ? proc_kcore_init+0x0/0xf1
 [<6010d574>] kcore_update_ram+0x4c/0x168
 [<6010d72e>] ? kclist_add+0x0/0x2e
 [<6000e943>] proc_kcore_init+0xea/0xf1
 [<6000e859>] ? proc_kcore_init+0x0/0xf1
 [<6000e859>] ? proc_kcore_init+0x0/0xf1
 [<600189f0>] do_one_initcall+0x13c/0x204
 [<6004ca46>] ? parse_args+0x1df/0x2e0
 [<6004c82d>] ? parameq+0x0/0x3a
 [<601b5990>] ? strcpy+0x0/0x18
 [<60001e1a>] kernel_init_freeable+0x240/0x31e
 [<6026f1c0>] kernel_init+0x12/0x148
 [<60019fad>] new_thread_handler+0x81/0xa3

Fixes 8c86e70ace ("resource: provide new functions to walk
through resources").

Reported-by: Daniel Walter <sahne@0x90.at>
Tested-by: Richard Weinberger <richard@nod.at>
Tested-by: Toralf Förster <toralf.foerster@gmx.de>
Tested-by: Daniel Walter <sahne@0x90.at>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-29 16:28:15 -07:00
..
bpf net: filter: split 'struct sk_filter' into socket and bpf parts 2014-08-02 15:03:58 -07:00
debug kdb: Use ktime_get_ts() 2014-06-12 16:18:45 +02:00
events Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-08-24 16:16:55 -07:00
gcov kernel/gcov/fs.c: remove unnecessary null test before debugfs_remove 2014-08-08 15:57:24 -07:00
irq Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-08-05 17:38:45 -07:00
locking arch, locking: Ciao arch_mutex_cpu_relax() 2014-07-17 12:32:47 +02:00
power Merge branches 'pm-sleep', 'pm-cpufreq' and 'pm-cpuidle' 2014-08-11 23:19:48 +02:00
printk printk: Add function to return log buffer address and size 2014-08-13 15:13:44 +10:00
rcu Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-08-04 15:55:08 -07:00
sched Merge branches 'pm-sleep', 'pm-cpufreq' and 'pm-cpuidle' 2014-08-11 23:19:48 +02:00
time timekeeping: Another fix to the VSYSCALL_OLD update_vsyscall 2014-08-14 11:04:11 -06:00
trace trace: Fix epoll hang when we race with new entries 2014-08-25 20:18:11 -04:00
.gitignore Ignore generated file kernel/x509_certificate_list 2013-12-10 18:21:34 +00:00
acct.c kernel/acct.c: fix coding style warnings and errors 2014-08-08 15:57:27 -07:00
async.c
audit_tree.c inotify: Fix reporting of cookies for inotify events 2014-02-18 11:17:17 +01:00
audit_watch.c inotify: Fix reporting of cookies for inotify events 2014-02-18 11:17:17 +01:00
audit.c CAPABILITIES: remove undefined caps from all processes 2014-07-24 21:53:47 +10:00
audit.h audit: Use struct net not pid_t to remember the network namespce to reply in 2014-03-20 10:10:53 -04:00
auditfilter.c kernel/auditfilter.c: replace count*size kmalloc by kcalloc 2014-08-06 18:01:12 -07:00
auditsc.c auditsc: audit_krule mask accesses need bounds checking 2014-06-10 08:44:40 -07:00
backtracetest.c kernel/backtracetest.c: replace no level printk by pr_info() 2014-06-04 16:54:14 -07:00
bounds.c page-cgroup: get rid of NR_PCG_FLAGS 2014-08-08 15:57:18 -07:00
capability.c CAPABILITIES: remove undefined caps from all processes 2014-07-24 21:53:47 +10:00
cgroup_freezer.c cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes 2014-07-15 11:05:09 -04:00
cgroup.c Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-08-04 10:11:28 -07:00
compat.c kernel/compat.c: use sizeof() instead of sizeof 2014-06-04 16:54:19 -07:00
configs.c
context_tracking.c x86/kprobes: Fix build errors and blacklist context_track_user 2014-06-14 09:07:44 +02:00
cpu_pm.c
cpu.c sched: Rework check_for_tasks() 2014-07-05 11:17:45 +02:00
cpuset.c Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-08-04 10:11:28 -07:00
crash_dump.c
cred.c
delayacct.c delayacct: Remove braindamaged type conversions 2014-07-23 10:18:06 -07:00
dma.c
elfcore.c switch elf_core_write_extra_phdrs() to dump_emit() 2013-11-09 00:16:23 -05:00
exec_domain.c kernel/exec_domain.c: code clean-up 2014-06-04 16:54:15 -07:00
exit.c kernel/exit.c: fix coding style warnings and errors 2014-08-08 15:57:22 -07:00
extable.c asmlinkage: Make main_extable_sort_needed visible 2014-02-13 18:13:22 -08:00
fork.c seccomp: Replace BUG(!spin_is_locked()) with assert_spin_lock 2014-08-11 13:29:12 -07:00
freezer.c libata, freezer: avoid block device removal while system is frozen 2013-12-19 13:50:32 -05:00
futex_compat.c compat: Get rid of (get|put)_compat_time(val|spec) 2014-02-02 14:09:12 -08:00
futex.c futex: Simplify futex_lock_pi_atomic() and make it more robust 2014-06-21 22:26:24 +02:00
groups.c kernel/groups.c: remove return value of set_groups 2014-04-03 16:21:05 -07:00
hung_task.c kernel/hung_task.c: convert simple_strtoul to kstrtouint 2014-06-04 16:54:15 -07:00
irq_work.c irq_work: Remove BUG_ON in irq_work_run() 2014-07-05 11:17:26 +02:00
jump_label.c static_key: WARN on usage before jump_label_init was called 2013-10-19 19:45:35 -04:00
kallsyms.c kernel/kallsyms.c: fix %pB when there's no symbol at the address 2014-08-08 15:57:18 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS 2013-11-15 09:32:22 +09:00
Kconfig.locks locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER 2014-07-16 14:57:13 +02:00
Kconfig.preempt
kexec.c kexec: verify the signature of signed PE bzImage 2014-08-08 15:57:33 -07:00
kmod.c signals: change wait_for_helper() to use kernel_sigaction() 2014-06-06 16:08:12 -07:00
kprobes.c kprobes: Skip kretprobe hit in NMI context to avoid deadlock 2014-08-08 10:38:04 +02:00
ksysfs.c kobject: Make support for uevent_helper optional. 2014-04-25 12:00:49 -07:00
kthread.c kthread_work: wake up worker only when the worker is idle 2014-07-28 14:07:52 -04:00
latencytop.c kernel/latencytop.c: convert seq_printf to seq_puts 2014-06-04 16:54:15 -07:00
Makefile bin2c: move bin2c in scripts/basic 2014-08-08 15:57:32 -07:00
module_signing.c keys: change asymmetric keys to use common hash definitions 2013-10-25 17:15:18 -04:00
module-internal.h
module.c module: Clean up ro/nx after early module load failures 2014-08-16 04:47:00 +09:30
notifier.c kprobes, notifier: Use NOKPROBE_SYMBOL macro in notifier 2014-04-24 10:26:39 +02:00
nsproxy.c namespaces: Use task_lock and not rcu to protect nsproxy 2014-07-29 18:08:50 -07:00
padata.c padata: Fix wrong usage of rcu_dereference() 2013-12-05 21:28:42 +08:00
panic.c panic: add TAINT_SOFTLOCKUP 2014-08-08 15:57:24 -07:00
params.c Add module param type 'ullong' 2014-07-17 22:07:37 +02:00
pid_namespace.c pid_namespace: pidns_get() should check task_active_pid_ns() != NULL 2014-04-02 16:20:21 -07:00
pid.c
profile.c kernel/profile.c: use static const char instead of static char 2014-06-06 16:08:13 -07:00
ptrace.c sched: Remove proliferation of wait_on_bit() action functions 2014-07-16 15:10:39 +02:00
range.c
reboot.c kernel/reboot.c: convert simple_strtoul to kstrtoint 2014-06-04 16:54:15 -07:00
relay.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
res_counter.c kernel/res_counter.c: replace simple_strtoull by kstrtoull 2014-06-04 16:54:15 -07:00
resource.c resource: fix the case of null pointer access 2014-08-29 16:28:15 -07:00
seccomp.c seccomp: Replace BUG(!spin_is_locked()) with assert_spin_lock 2014-08-11 13:29:12 -07:00
signal.c Merge branch 'signal-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2014-08-09 09:58:12 -07:00
smp.c kernel/smp.c:on_each_cpu_cond(): fix warning in fallback path 2014-08-06 18:01:22 -07:00
smpboot.c
smpboot.h
softirq.c Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2014-05-22 11:36:10 +02:00
stacktrace.c
stop_machine.c kernel/stop_machine.c: kernel-doc warning fix 2014-06-04 16:54:15 -07:00
sys_ni.c kexec: new syscall kexec_file_load() declaration 2014-08-08 15:57:32 -07:00
sys.c sched: move no_new_privs into new atomic flags 2014-07-18 12:13:38 -07:00
sysctl_binary.c ipv6: Allow accepting RA from local IP addresses. 2014-07-01 12:16:24 -07:00
sysctl.c mm, hugetlb: remove hugetlb_zero and hugetlb_infinity 2014-08-06 18:01:19 -07:00
system_certificates.S KEYS: correct alignment of system_certificate_list content in assembly file 2013-12-10 18:25:28 +00:00
system_keyring.c KEYS: validate certificate trust only with builtin keys 2014-07-17 09:35:17 -04:00
task_work.c
taskstats.c genetlink: only pass array to genl_register_family_with_ops() 2013-11-19 16:39:05 -05:00
test_kprobes.c kernel/test_kprobes.c: use current logging functions 2014-08-08 15:57:18 -07:00
torture.c torture: Avoid format string leak to thead name 2014-07-07 10:12:56 -07:00
tracepoint.c tracing: syscall_regfunc() should not skip kernel threads 2014-06-21 00:15:26 -04:00
tsacct.c sched: Make task->start_time nanoseconds based 2014-07-23 10:18:05 -07:00
uid16.c
up.c smp: Rename __smp_call_function_single() to smp_call_function_single_async() 2014-02-24 14:47:15 -08:00
user_namespace.c proc: constify seq_operations 2014-08-08 15:57:22 -07:00
user-return-notifier.c
user.c kernel/user.c: drop unused field 'files' from user_struct 2014-06-04 16:54:16 -07:00
utsname_sysctl.c sysctl: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:16 -07:00
utsname.c namespaces: Use task_lock and not rcu to protect nsproxy 2014-07-29 18:08:50 -07:00
watchdog.c panic: add TAINT_SOFTLOCKUP 2014-08-08 15:57:24 -07:00
workqueue_internal.h workqueue: rename manager_mutex to attach_mutex 2014-05-20 10:59:32 -04:00
workqueue.c Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2014-08-04 10:09:27 -07:00