Eric W. Biederman
117433236a
exec: Transform exec_update_mutex into a rw_semaphore ...
[ Upstream commit f7cfd871ae0c5008d94b6f66834e7845caa93c15 ]
Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex. The problematic lock ordering found by lockdep
was:
perf_event_open (exec_update_mutex -> ovl_i_mutex)
chown (ovl_i_mutex -> sb_writes)
sendfile (sb_writes -> p->lock)
by reading from a proc file and writing to overlayfs
proc_pid_syscall (p->lock -> exec_update_mutex)
While looking at possible solutions it occured to me that all of the
users and possible users involved only wanted to state of the given
process to remain the same. They are all readers. The only writer is
exec.
There is no reason for readers to block on each other. So fix
this deadlock by transforming exec_update_mutex into a rw_semaphore
named exec_update_lock that only exec takes for writing.
Cc: Jann Horn <jannh@google.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christopher Yeoh <cyeoh@au1.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Fixes: eea9673250db ("exec: Add exec_update_mutex to replace cred_guard_mutex")
[0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com
Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-01-09 13:44:55 +01:00
bpf: Zero-fill re-used per-cpu map element
2020-11-18 19:20:26 +01:00
cgroup: Fix memory leak when parsing multiple source parameters
2021-01-06 14:48:37 +01:00
kgdb: Make "kgdbcon" work properly with "kgdb_earlycon"
2020-11-05 11:43:16 +01:00
swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"
2020-11-18 19:20:32 +01:00
exec: Transform exec_update_mutex into a rw_semaphore
2021-01-09 13:44:55 +01:00
gcov: add support for GCC 10.1
2020-09-17 13:47:56 +02:00
genirq/irqdomain: Don't try to free an interrupt that has no mapping
2020-12-30 11:51:14 +01:00
livepatch: Nullify obj->mod in klp_module_coming()'s error path
2019-08-19 13:03:37 +02:00
exec: Transform exec_update_mutex into a rw_semaphore
2021-01-09 13:44:55 +01:00
PM: hibernate: remove the bogus call to get_gendisk() in software_resume()
2020-10-29 09:58:04 +01:00
printk: handle blank console arguments passed in.
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arm64: smp: Tell RCU about CPUs that fail to come online
2020-11-24 13:29:01 +01:00
sched: Reenable interrupts in do_sched_yield()
2020-12-30 11:51:03 +01:00
tick/sched: Remove bogus boot "safety" check
2021-01-06 14:48:40 +01:00
Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"
2020-12-30 11:51:47 +01:00
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:30:59 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:30:59 +02:00
audit: CONFIG_CHANGE don't log internal bookkeeping as an event
2020-10-01 13:17:32 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:30:59 +02:00
kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling
2020-12-30 11:50:56 +01:00
kernel/cpu_pm: Fix uninitted local in cpu_pm
2020-06-22 09:31:22 +02:00
keys: Fix request_key() cache
2020-01-17 19:48:42 +01:00
kernel/elfcore.c: include proper prototypes
2019-09-25 17:51:39 -07:00
don't dump the threads that had been already exiting when zapped.
2020-11-18 19:20:31 +01:00
extable: Add function to search only kernel exception table
2019-08-21 22:23:48 +10:00
fail_function: Remove a redundant mutex unlock
2020-11-24 13:29:18 +01:00
exec: Transform exec_update_mutex into a rw_semaphore
2021-01-09 13:44:55 +01:00
Revert "libata, freezer: avoid block device removal while system is frozen"
2019-10-06 09:11:37 -06:00
futex: Don't enable IRQs unconditionally in put_pi_state()
2020-11-18 19:20:30 +01:00
kbuild: add variables for compression tools
2020-09-03 11:27:10 +02:00
jump_label: Don't warn on __exit jump entries
2019-08-29 15:10:10 +01:00
kallsyms: Refactor kallsyms_show_value() to take cred
2020-07-16 08:16:44 +02:00
exec: Transform exec_update_mutex into a rw_semaphore
2021-01-09 13:44:55 +01:00
kexec_load: Disable at runtime if the kernel is locked down
2019-08-19 21:54:15 -07:00
kexec: bail out upon SIGKILL when allocating memory.
2019-09-25 17:51:40 -07:00
kexec_elf: support 32 bit ELF files
2019-09-06 23:58:44 +02:00
Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2019-09-28 08:14:15 -07:00
kmod: make request_module() return an error when autoloading is disabled
2020-04-17 10:50:22 +02:00
kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE
2020-10-01 13:18:25 +02:00
kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled
2020-11-10 12:37:27 +01:00
kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
2020-10-01 13:17:10 +02:00
module: delay kobject uevent until after module init call
2021-01-06 14:48:40 +01:00
kernel/notifier.c: intercept duplicate registrations to avoid infinite loops
2020-10-01 13:17:23 +02:00
padata: add separate cpuhp node for CPUHP_PADATA_DEAD
2020-06-17 16:40:22 +02:00
panic: ensure preemption is disabled during panic()
2019-10-07 15:47:19 -07:00
lockdown: Lock down module params that specify hardware parameters (eg. ioport)
2019-08-19 21:54:16 -07:00
ptrace: Set PF_SUPERPRIV when checking capability
2020-11-24 13:29:24 +01:00
reboot: fix overflow parsing reboot cpu number
2020-11-18 19:20:30 +01:00
kernel/relay.c: fix memleak on destroy relay channel
2020-08-26 10:40:51 +02:00
/dev/mem: Revoke mappings when a driver claims the region
2020-06-24 17:50:35 +02:00
seccomp: Set PF_SUPERPRIV when checking capability
2020-11-24 13:29:24 +01:00
ptrace: fix task_join_group_stop() for the case when current is traced
2020-11-10 12:37:24 +01:00
stacktrace: Don't skip first entry on noncurrent tasks
2019-11-04 21:19:25 +01:00
stop_machine: Avoid potential race behaviour
2019-10-17 12:47:12 +02:00
kernel/sys.c: avoid copying possible padding bytes in copy_to_user
2020-10-01 13:17:23 +02:00
kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
2020-10-01 13:17:10 +02:00
kernel: sysctl: make drop_caches write-only
2020-01-04 19:18:32 +01:00
taskstats: fix data-race
2020-01-09 10:19:54 +01:00
usermodehelper: reset umask to default before executing user process
2020-10-14 10:32:58 +02:00
watchdog/softlockup: Enforce that timestamp is valid on boot
2020-02-24 08:36:52 +01:00
workqueue: Remove the warning in wq_worker_sleeping()
2020-10-01 13:17:54 +02:00
117433236a