blackbird-obmc-linux/kernel/trace, branch dev-5.0-raptor-04-16-2019

tracing: kdb: Fix ftdump to not sleep

2019-04-05T20:34:19+00:00

[ Upstream commit 31b265b3baaf55f209229888b7ffea523ddab366 ] As reported back in 2016-11 [1], the "ftdump" kdb command triggers a BUG for "sleeping function called from invalid context". kdb's "ftdump" command wants to call ring_buffer_read_prepare() in atomic context. A very simple solution for this is to add allocation flags to ring_buffer_read_prepare() so kdb can call it without triggering the allocation error. This patch does that. Note that in the original email thread about this, it was suggested that perhaps the solution for kdb was to either preallocate the buffer ahead of time or create our own iterator. I'm hoping that this alternative of adding allocation flags to ring_buffer_read_prepare() can be considered since it means I don't need to duplicate more of the core trace code into "trace_kdb.c" (for either creating my own iterator or re-preparing a ring allocator whose memory was already allocated). NOTE: another option for kdb is to actually figure out how to make it reuse the existing ftrace_dump() function and totally eliminate the duplication. This sounds very appealing and actually works (the "sr z" command can be seen to properly dump the ftrace buffer). The downside here is that ftrace_dump() fully consumes the trace buffer. Unless that is changed I'd rather not use it because it means "ftdump | grep xyz" won't be very useful to search the ftrace buffer since it will throw away the whole trace on the first grep. A future patch to dump only the last few lines of the buffer will also be hard to implement. [1] https://lkml.kernel.org/r/20161117191605.GA21459@google.com Link: http://lkml.kernel.org/r/20190308193205.213659-1-dianders@chromium.org Reported-by: Brian Norris Signed-off-by: Douglas Anderson Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Sasha Levin

tracing: initialize variable in create_dyn_event()

2019-04-03T04:27:28+00:00

commit 3dee10da2e9ff220e054a8f158cc296c797fbe81 upstream. Fix compile warning in create_dyn_event(): 'ret' may be used uninitialized in this function [-Wuninitialized]. Link: http://lkml.kernel.org/r/1553237900-8555-1-git-send-email-frowand.list@gmail.com Cc: Masami Hiramatsu Cc: Ingo Molnar Cc: Tom Zanussi Cc: Ravi Bangoria Cc: stable@vger.kernel.org Fixes: 5448d44c3855 ("tracing: Add unified dynamic event framework") Signed-off-by: Frank Rowand Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing/perf: Use strndup_user() instead of buggy open-coded version

2019-03-23T19:11:17+00:00

commit 83540fbc8812a580b6ad8f93f4c29e62e417687e upstream. The first version of this method was missing the check for `ret == PATH_MAX`; then such a check was added, but it didn't call kfree() on error, so there was still a small memory leak in the error case. Fix it by using strndup_user() instead of open-coding it. Link: http://lkml.kernel.org/r/20190220165443.152385-1-jannh@google.com Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: 0eadcc7a7bc0 ("perf/core: Fix perf_uprobe_init()") Reviewed-by: Masami Hiramatsu Acked-by: Song Liu Signed-off-by: Jann Horn Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: Do not free iter->trace in fail path of tracing_open_pipe()

2019-03-23T19:11:17+00:00

commit e7f0c424d0806b05d6f47be9f202b037eb701707 upstream. Commit d716ff71dd12 ("tracing: Remove taking of trace_types_lock in pipe files") use the current tracer instead of the copy in tracing_open_pipe(), but it forget to remove the freeing sentence in the error path. There's an error path that can call kfree(iter->trace) after the iter->trace was assigned to tr->current_trace, which would be bad to free. Link: http://lkml.kernel.org/r/1550060946-45984-1-git-send-email-yi.zhang@huawei.com Cc: stable@vger.kernel.org Fixes: d716ff71dd12 ("tracing: Remove taking of trace_types_lock in pipe files") Signed-off-by: zhangyi (F) Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: Use strncpy instead of memcpy for string keys in hist triggers

2019-03-23T19:11:17+00:00

commit 9f0bbf3115ca9f91f43b7c74e9ac7d79f47fc6c2 upstream. Because there may be random garbage beyond a string's null terminator, it's not correct to copy the the complete character array for use as a hist trigger key. This results in multiple histogram entries for the 'same' string key. So, in the case of a string key, use strncpy instead of memcpy to avoid copying in the extra bytes. Before, using the gdbus entries in the following hist trigger as an example: # echo 'hist:key=comm' > /sys/kernel/debug/tracing/events/sched/sched_waking/trigger # cat /sys/kernel/debug/tracing/events/sched/sched_waking/hist ... { comm: ImgDecoder #4 } hitcount: 203 { comm: gmain } hitcount: 213 { comm: gmain } hitcount: 216 { comm: StreamTrans #73 } hitcount: 221 { comm: mozStorage #3 } hitcount: 230 { comm: gdbus } hitcount: 233 { comm: StyleThread#5 } hitcount: 253 { comm: gdbus } hitcount: 256 { comm: gdbus } hitcount: 260 { comm: StyleThread#4 } hitcount: 271 ... # cat /sys/kernel/debug/tracing/events/sched/sched_waking/hist | egrep gdbus | wc -l 51 After: # cat /sys/kernel/debug/tracing/events/sched/sched_waking/hist | egrep gdbus | wc -l 1 Link: http://lkml.kernel.org/r/50c35ae1267d64eee975b8125e151e600071d4dc.1549309756.git.tom.zanussi@linux.intel.com Cc: Namhyung Kim Cc: stable@vger.kernel.org Fixes: 79e577cbce4c4 ("tracing: Support string type key properly") Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: Fix event filters and triggers to handle negative numbers

2019-03-10T06:09:00+00:00

commit 6a072128d262d2b98d31626906a96700d1fc11eb upstream. Then tracing syscall exit event it is extremely useful to filter exit codes equal to some negative value, to react only to required errors. But negative numbers does not work: [root@snorch sys_exit_read]# echo "ret == -1" > filter bash: echo: write error: Invalid argument [root@snorch sys_exit_read]# cat filter ret == -1 ^ parse_error: Invalid value (did you forget quotes)? Similar thing happens when setting triggers. These is a regression in v4.17 introduced by the commit mentioned below, testing without these commit shows no problem with negative numbers. Link: http://lkml.kernel.org/r/20180823102534.7642-1-ptikhomirov@virtuozzo.com Cc: stable@vger.kernel.org Fixes: 80765597bc58 ("tracing: Rewrite filter logic to be simpler and faster") Signed-off-by: Pavel Tikhomirov Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

Merge tag 'trace-v5.0-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2019-02-18T17:40:16+00:00

Pull tracing fixes from Steven Rostedt: "Two more tracing fixes - Have kprobes not use copy_from_user() to access kernel addresses, because kprobes can legitimately poke at bad kernel memory, which will fault. Copy from user code should never fault in kernel space. Using probe_mem_read() can handle kernel address space faulting. - Put back the entries counter in the tracing output that was accidentally removed" * tag 'trace-v5.0-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix number of entries in trace header kprobe: Do not use uaccess functions to access kernel memory that can fault

tracing: Fix number of entries in trace header

2019-02-15T17:42:26+00:00

The following commit 441dae8f2f29 ("tracing: Add support for display of tgid in trace output") removed the call to print_event_info() from print_func_help_header_irq() which results in the ftrace header not reporting the number of entries written in the buffer. As this wasn't the original intent of the patch, re-introduce the call to print_event_info() to restore the orginal behaviour. Link: http://lkml.kernel.org/r/20190214152950.4179-1-quentin.perret@arm.com Acked-by: Joel Fernandes Cc: stable@vger.kernel.org Fixes: 441dae8f2f29 ("tracing: Add support for display of tgid in trace output") Signed-off-by: Quentin Perret Signed-off-by: Steven Rostedt (VMware)

kprobe: Do not use uaccess functions to access kernel memory that can fault

2019-02-15T17:41:23+00:00

The userspace can ask kprobe to intercept strings at any memory address, including invalid kernel address. In this case, fetch_store_strlen() would crash since it uses general usercopy function, and user access functions are no longer allowed to access kernel memory. For example, we can crash the kernel by doing something as below: $ sudo kprobe 'p:do_sys_open +0(+0(%si)):string' [ 103.620391] BUG: GPF in non-whitelisted uaccess (non-canonical address?) [ 103.622104] general protection fault: 0000 [#1] SMP PTI [ 103.623424] CPU: 10 PID: 1046 Comm: cat Not tainted 5.0.0-rc3-00130-gd73aba1-dirty #96 [ 103.625321] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-2-g628b2e6-dirty-20190104_103505-linux 04/01/2014 [ 103.628284] RIP: 0010:process_fetch_insn+0x1ab/0x4b0 [ 103.629518] Code: 10 83 80 28 2e 00 00 01 31 d2 31 ff 48 8b 74 24 28 eb 0c 81 fa ff 0f 00 00 7f 1c 85 c0 75 18 66 66 90 0f ae e8 48 63 ca 89 f8 <8a> 0c 31 66 66 90 83 c2 01 84 c9 75 dc 89 54 24 34 89 44 24 28 48 [ 103.634032] RSP: 0018:ffff88845eb37ce0 EFLAGS: 00010246 [ 103.635312] RAX: 0000000000000000 RBX: ffff888456c4e5a8 RCX: 0000000000000000 [ 103.637057] RDX: 0000000000000000 RSI: 2e646c2f6374652f RDI: 0000000000000000 [ 103.638795] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 103.640556] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 [ 103.642297] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 103.644040] FS: 0000000000000000(0000) GS:ffff88846f000000(0000) knlGS:0000000000000000 [ 103.646019] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 103.647436] CR2: 00007ffc79758038 CR3: 0000000463360006 CR4: 0000000000020ee0 [ 103.649147] Call Trace: [ 103.649781] ? sched_clock_cpu+0xc/0xa0 [ 103.650747] ? do_sys_open+0x5/0x220 [ 103.651635] kprobe_trace_func+0x303/0x380 [ 103.652645] ? do_sys_open+0x5/0x220 [ 103.653528] kprobe_dispatcher+0x45/0x50 [ 103.654682] ? do_sys_open+0x1/0x220 [ 103.655875] kprobe_ftrace_handler+0x90/0xf0 [ 103.657282] ftrace_ops_assist_func+0x54/0xf0 [ 103.658564] ? __call_rcu+0x1dc/0x280 [ 103.659482] 0xffffffffc00000bf [ 103.660384] ? __ia32_sys_open+0x20/0x20 [ 103.661682] ? do_sys_open+0x1/0x220 [ 103.662863] do_sys_open+0x5/0x220 [ 103.663988] do_syscall_64+0x60/0x210 [ 103.665201] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 103.666862] RIP: 0033:0x7fc22fadccdd [ 103.668034] Code: 48 89 54 24 e0 41 83 e2 40 75 32 89 f0 25 00 00 41 00 3d 00 00 41 00 74 24 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 33 f3 c3 66 0f 1f 84 00 00 00 00 00 48 8d 44 [ 103.674029] RSP: 002b:00007ffc7972c3a8 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 [ 103.676512] RAX: ffffffffffffffda RBX: 0000562f86147a21 RCX: 00007fc22fadccdd [ 103.678853] RDX: 0000000000080000 RSI: 00007fc22fae1428 RDI: 00000000ffffff9c [ 103.681151] RBP: ffffffffffffffff R08: 0000000000000000 R09: 0000000000000000 [ 103.683489] R10: 0000000000000000 R11: 0000000000000287 R12: 00007fc22fce90a8 [ 103.685774] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 [ 103.688056] Modules linked in: [ 103.689131] ---[ end trace 43792035c28984a1 ]--- This can be fixed by using probe_mem_read() instead, as it can handle faulting kernel memory addresses, which kprobes can legitimately do. Link: http://lkml.kernel.org/r/20190125151051.7381-1-changbin.du@gmail.com Cc: stable@vger.kernel.org Fixes: 9da3f2b7405 ("x86/fault: BUG() when uaccess helpers fault on kernel addresses") Signed-off-by: Changbin Du Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2019-02-13T18:28:17+00:00

Pull tracing fix from Steven Rostedt: "This fixes kprobes/uprobes dynamic processing of strings, where it processes the args but does not update the remaining length of the buffer that the string arguments will be placed in. It constantly passes in the total size of buffer used instead of passing in the remaining size of the buffer used. This could cause issues if the strings are larger than the max size of an event which could cause the strings to be written beyond what was reserved on the buffer" * tag 'trace-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: probeevent: Correctly update remaining space in dynamic area