Song Liu 82c888e51c ftrace: Clean up hash direct_functions on register failures ... commit 7d54c15cb89a29a5f59e5ffc9ee62e6591769ef1 upstream. We see the following GPF when register_ftrace_direct fails: [ ] general protection fault, probably for non-canonical address \ 0x200000000000010: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [...] [ ] RIP: 0010:ftrace_find_rec_direct+0x53/0x70 [ ] Code: 48 c1 e0 03 48 03 42 08 48 8b 10 31 c0 48 85 d2 74 [...] [ ] RSP: 0018:ffffc9000138bc10 EFLAGS: 00010206 [ ] RAX: 0000000000000000 RBX: ffffffff813e0df0 RCX: 000000000000003b [ ] RDX: 0200000000000000 RSI: 000000000000000c RDI: ffffffff813e0df0 [ ] RBP: ffffffffa00a3000 R08: ffffffff81180ce0 R09: 0000000000000001 [ ] R10: ffffc9000138bc18 R11: 0000000000000001 R12: ffffffff813e0df0 [ ] R13: ffffffff813e0df0 R14: ffff888171b56400 R15: 0000000000000000 [ ] FS: 00007fa9420c7780(0000) GS:ffff888ff6a00000(0000) knlGS:000000000 [ ] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ ] CR2: 000000000770d000 CR3: 0000000107d50003 CR4: 0000000000370ee0 [ ] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ ] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ ] Call Trace: [ ] <TASK> [ ] register_ftrace_direct+0x54/0x290 [ ] ? render_sigset_t+0xa0/0xa0 [ ] bpf_trampoline_update+0x3f5/0x4a0 [ ] ? 0xffffffffa00a3000 [ ] bpf_trampoline_link_prog+0xa9/0x140 [ ] bpf_tracing_prog_attach+0x1dc/0x450 [ ] bpf_raw_tracepoint_open+0x9a/0x1e0 [ ] ? find_held_lock+0x2d/0x90 [ ] ? lock_release+0x150/0x430 [ ] __sys_bpf+0xbd6/0x2700 [ ] ? lock_is_held_type+0xd8/0x130 [ ] __x64_sys_bpf+0x1c/0x20 [ ] do_syscall_64+0x3a/0x80 [ ] entry_SYSCALL_64_after_hwframe+0x44/0xae [ ] RIP: 0033:0x7fa9421defa9 [ ] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 9 f8 [...] [ ] RSP: 002b:00007ffed743bd78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 [ ] RAX: ffffffffffffffda RBX: 00000000069d2480 RCX: 00007fa9421defa9 [ ] RDX: 0000000000000078 RSI: 00007ffed743bd80 RDI: 0000000000000011 [ ] RBP: 00007ffed743be00 R08: 0000000000bb7270 R09: 0000000000000000 [ ] R10: 00000000069da210 R11: 0000000000000246 R12: 0000000000000001 [ ] R13: 00007ffed743c4b0 R14: 00000000069d2480 R15: 0000000000000001 [ ] </TASK> [ ] Modules linked in: klp_vm(OK) [ ] ---[ end trace 0000000000000000 ]--- One way to trigger this is: 1. load a livepatch that patches kernel function xxx; 2. run bpftrace -e 'kfunc:xxx {}', this will fail (expected for now); 3. repeat #2 => gpf. This is because the entry is added to direct_functions, but not removed. Fix this by remove the entry from direct_functions when register_ftrace_direct fails. Also remove the last trailing space from ftrace.c, so we don't have to worry about it anymore. Link: https://lkml.kernel.org/r/20220524170839.900849-1-song@kernel.org Cc: stable@vger.kernel.org Fixes: 763e34e74b ("ftrace: Add register_ftrace_direct()") Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-06-09 10:21:26 +02:00
..
blktrace.c	blktrace: Fix uaf in blk_trace access after removing by sysfs	2021-09-30 10:11:05 +02:00
bpf_trace.c	bpf: Remove config check to enable bpf support for branch records	2022-01-27 10:53:54 +01:00
bpf_trace.h
fgraph.c
ftrace_internal.h
ftrace.c	ftrace: Clean up hash direct_functions on register failures	2022-06-09 10:21:26 +02:00
Kconfig
kprobe_event_gen_test.c
Makefile
power-traces.c
preemptirq_delay_test.c
ring_buffer_benchmark.c
ring_buffer.c	ring-buffer: Protect ring_buffer_reset() from reentrancy	2021-11-18 14:03:49 +01:00
rpm-traces.c
synth_event_gen_test.c
trace_benchmark.c
trace_benchmark.h
trace_boot.c	tracing/boot: Fix a hist trigger dependency for boot time tracing	2021-09-22 12:28:03 +02:00
trace_branch.c
trace_clock.c
trace_dynevent.c
trace_dynevent.h
trace_entries.h
trace_event_perf.c
trace_events_filter_test.h
trace_events_filter.c	tracing: Add ustring operation to filtering string pointers	2022-03-08 19:09:31 +01:00
trace_events_hist.c	tracing: Fix potential double free in create_var_ref()	2022-06-09 10:21:23 +02:00
trace_events_inject.c
trace_events_synth.c
trace_events_trigger.c	tracing: Dump stacktrace trigger to the corresponding instance	2022-04-27 13:53:46 +02:00
trace_events.c	tracing: Check pid filtering when creating events	2021-12-01 09:19:09 +01:00
trace_export.c
trace_functions_graph.c
trace_functions.c	tracing: Have all levels of checks prevent recursion	2021-10-27 09:56:56 +02:00
trace_hwlat.c
trace_irqsoff.c
trace_kdb.c
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c	tracing: Fix return value of __setup handlers	2022-03-08 19:09:38 +01:00
trace_mmiotrace.c
trace_nop.c
trace_output.c
trace_output.h
trace_preemptirq.c
trace_printk.c
trace_probe_tmpl.h
trace_probe.c	tracing/probes: Reject events which have the same name of existing one	2021-09-22 12:28:00 +02:00
trace_probe.h	tracing/probes: Reject events which have the same name of existing one	2021-09-22 12:28:00 +02:00
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest_dynamic.c
trace_selftest.c
trace_seq.c
trace_stack.c
trace_stat.c
trace_stat.h
trace_synth.h	tracing: Synthetic event field_pos is an index not a boolean	2021-07-28 14:35:45 +02:00
trace_syscalls.c
trace_uprobe.c	tracing/uprobe: Fix uprobe_perf_open probes iteration	2021-12-01 09:19:01 +01:00
trace.c	tracing: Ensure trace buffer is at least 4096 bytes large	2022-03-16 14:16:00 +01:00
trace.h	tracing: Fix pid filtering when triggers are attached	2021-12-01 09:19:01 +01:00
tracing_map.c	tracing: Fix a kmemleak false positive in tracing_map	2021-12-17 10:14:40 +01:00
tracing_map.h