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alistair23-linux/kernel/trace
Jan Kara 6f9cff84dd blktrace: Protect q->blk_trace with RCU
[ Upstream commit c780e86dd4 ]

KASAN is reporting that __blk_add_trace() has a use-after-free issue
when accessing q->blk_trace. Indeed the switching of block tracing (and
thus eventual freeing of q->blk_trace) is completely unsynchronized with
the currently running tracing and thus it can happen that the blk_trace
structure is being freed just while __blk_add_trace() works on it.
Protect accesses to q->blk_trace by RCU during tracing and make sure we
wait for the end of RCU grace period when shutting down tracing. Luckily
that is rare enough event that we can afford that. Note that postponing
the freeing of blk_trace to an RCU callback should better be avoided as
it could have unexpected user visible side-effects as debugfs files
would be still existing for a short while block tracing has been shut
down.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=205711
CC: stable@vger.kernel.org
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reported-by: Tristan Madani <tristmd@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-03-05 16:43:52 +01:00
..
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
Makefile tracing: Add unified dynamic event framework 2018-12-08 20:54:09 -05:00
blktrace.c blktrace: Protect q->blk_trace with RCU 2020-03-05 16:43:52 +01:00
bpf_trace.c bpf: Make use of probe_user_write in probe write helper 2020-01-17 19:48:40 +01:00
fgraph.c ftrace: Look up the address of return_to_handler() using helpers 2019-09-18 12:24:47 +10:00
ftrace.c ftrace: fpid_next() should increase position index 2020-02-24 08:36:59 +01:00
ftrace_internal.h treewide: Rename rcu_dereference_raw_notrace() to _check() 2019-08-01 14:16:21 -07:00
power-traces.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
preemptirq_delay_test.c tracing: Use trace_clock_local() for looping in preemptirq_delay_test.c 2018-10-17 15:35:33 -04:00
ring_buffer.c tracing: Do not create directories if lockdown is in affect 2020-01-12 12:21:45 +01:00
ring_buffer_benchmark.c tracing: Use CONFIG_PREEMPTION 2019-07-31 19:03:35 +02:00
rpm-traces.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace.c tracing: Disable trace_printk() on post poned tests 2020-03-05 16:43:43 +01:00
trace.h ftrace: Protect ftrace_graph_hash with ftrace_sync 2020-02-11 04:35:28 -08:00
trace_benchmark.c rcu: Rename cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs() 2018-05-15 10:27:29 -07:00
trace_benchmark.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_branch.c x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP 2019-04-03 11:02:24 +02:00
trace_clock.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_dynevent.c tracing: Add tracing_check_open_get_tr() 2019-10-12 20:44:07 -04:00
trace_dynevent.h tracing/dynevent: Pass extra arguments to match operation 2019-08-31 12:19:38 -04:00
trace_entries.h tracing: Change the function format to display function names by perf 2019-02-11 14:53:43 -05:00
trace_event_perf.c tracing: Fix race in perf_trace_buf initialization 2019-10-21 19:38:28 -04:00
trace_events.c tracing: Fix lock inversion in trace_event_enable_tgid_record() 2020-01-09 10:19:59 +01:00
trace_events_filter.c tracing: Avoid memory leak in process_system_preds() 2020-01-09 10:20:00 +01:00
trace_events_filter_test.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_events_hist.c tracing: Simplify assignment parsing for hist triggers 2020-02-24 08:36:31 +01:00
trace_events_trigger.c trigger_next should increase position index 2020-02-24 08:36:59 +01:00
trace_export.c tracing: Add trigger file for trace_markers tracefs/ftrace/print 2018-05-29 08:28:53 -04:00
trace_functions.c tracing: Update stack trace skipping for ORC unwinder 2018-01-23 15:57:00 -05:00
trace_functions_graph.c fgraph: Remove redundant ftrace_graph_notrace_addr() test 2019-07-30 21:50:03 -04:00
trace_hwlat.c tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency 2019-10-12 20:49:33 -04:00
trace_irqsoff.c The biggest change for this release is in the histogram code. 2019-03-11 17:01:32 -07:00
trace_kdb.c tracing: Silence GCC 9 array bounds warning 2019-05-25 23:04:30 -04:00
trace_kprobe.c tracing/uprobe: Fix to make trace_uprobe_filter alignment safe 2020-02-05 21:22:53 +00:00
trace_kprobe_selftest.c selftest/ftrace: Move kprobe selftest function to separate compile unit 2018-07-30 18:41:04 -04:00
trace_kprobe_selftest.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_mmiotrace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_nop.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_output.c tracing: Be more clever when dumping hex in __print_hex() 2019-09-17 11:21:28 -04:00
trace_output.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_preemptirq.c kprobes: Prohibit probing on hardirq tracers 2019-02-13 08:16:40 +01:00
trace_printk.c tracing: Add locked_down checks to the open calls of files created for tracefs 2019-10-12 20:48:06 -04:00
trace_probe.c tracing/kprobes: Have uname use __get_str() in print_fmt 2020-02-11 04:35:07 -08:00
trace_probe.h tracing/uprobe: Fix to make trace_uprobe_filter alignment safe 2020-02-05 21:22:53 +00:00
trace_probe_tmpl.h tracing/probe: Support user-space dereference 2019-05-25 23:04:42 -04:00
trace_sched_switch.c tracing: Fix sched switch start/stop refcount racy updates 2020-02-11 04:35:07 -08:00
trace_sched_wakeup.c kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail 2020-01-14 20:08:22 +01:00
trace_selftest.c function_graph: Have selftest also emulate tr->reset() as it did with tr->init() 2019-04-21 19:46:56 -04:00
trace_selftest_dynamic.c ftrace: Mark function tracer test functions noinline/noclone 2018-01-23 15:57:29 -05:00
trace_seq.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_stack.c tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined 2020-01-14 20:08:22 +01:00
trace_stat.c tracing: Fix very unlikely race of registering two stat tracers 2020-02-24 08:36:30 +01:00
trace_stat.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_syscalls.c syscalls: Remove start and number from syscall_get_arguments() args 2019-04-05 09:26:43 -04:00
trace_uprobe.c tracing/uprobe: Fix to make trace_uprobe_filter alignment safe 2020-02-05 21:22:53 +00:00
tracing_map.c tracing: Have the histogram compare functions convert to u64 first 2020-01-09 10:20:00 +01:00
tracing_map.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00