[Bug 1146141] New: bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null)

bugzilla_noreply＠novell.com

19 Aug 2019 19 Aug '19

12:05

http://bugzilla.suse.com/show_bug.cgi?id=1146141 Bug ID: 1146141 Summary: bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null) Classification: openSUSE Product: openSUSE Distribution Version: Leap 15.1 Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-maintainers@forge.provo.novell.com Reporter: aojeagarcia@suse.com QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- Created attachment 814495 --> http://bugzilla.suse.com/attachment.cgi?id=814495&action=edit kernel stack trace Kernel crash after using the bpftrace hello world example How to reproduce 1. Clone bpftrace # git clone https://github.com/iovisor/bpftrace.git 2. Build bpftrace using the release scripts (use a container to build it statically linked) # cd bpftrace # ./build.sh 3. Execute hello world example # build-release/src/bpftrace -e 'BEGIN { printf("hello world\n"); }' (kernel stack trace attached) -- You are receiving this mail because: You are on the CC list for the bug.

Attachments:

attachment.htm (text/html — 2.9 KB)

Show replies by date

bugzilla_noreply＠novell.com

19 Aug 19 Aug

13:43

New subject: [Bug 1146141] bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null)

http://bugzilla.suse.com/show_bug.cgi?id=1146141 Takashi Iwai changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |glin@suse.com, | |tiwai@suse.com, | |tonyj@suse.com -- You are receiving this mail because: You are on the CC list for the bug.

bugzilla_noreply＠novell.com

20 Aug 20 Aug

06:33

New subject: [Bug 1146141] bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null)

http://bugzilla.suse.com/show_bug.cgi?id=1146141 http://bugzilla.suse.com/show_bug.cgi?id=1146141#c1 --- Comment #1 from Gary Ching-Pang Lin --- The "hello world" example(*) comes with a "BEGIN" which makes bpftrace attach a uprobe event to an empty function "BEGIN_trigger" in bpftrace binary, and the crash happened when bpftrace tried to create the uprobe event for "BEGIN_trigger". Will look at the kernel code to find more clues. (*) # bpftrace -e 'BEGIN { printf("hello world\n"); }' -- You are receiving this mail because: You are on the CC list for the bug.

bugzilla_noreply＠novell.com

10:39

New subject: [Bug 1146141] bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null)

http://bugzilla.suse.com/show_bug.cgi?id=1146141 http://bugzilla.suse.com/show_bug.cgi?id=1146141#c2 Gary Ching-Pang Lin changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |pmladek@suse.com Flags| |needinfo?(pmladek@suse.com) --- Comment #2 from Gary Ching-Pang Lin --- It seems that the kernel crashed at "include/linux/dcache.h:d_real()" if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) "tu->path.dentry" in probe_event_enable() was supposed to be initialized in create_local_trace_uprobe() but it seems not. I found that the patch for bsc#1120046 omitted the part for "create_local_trace_uprobe()" and I suspected this is why "tu->path" wasn't initialized. Petr, Did you intend to skip the change for "create_local_trace_uprobe()" in tracing-Fix-bad-use-of-igrab-in-trace_uprobe.c.patch? -- You are receiving this mail because: You are on the CC list for the bug.

bugzilla_noreply＠novell.com

11:30

New subject: [Bug 1146141] bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null)

http://bugzilla.suse.com/show_bug.cgi?id=1146141 http://bugzilla.suse.com/show_bug.cgi?id=1146141#c3 Antonio Ojea changed: What |Removed |Added ---------------------------------------------------------------------------- Flags|needinfo?(pmladek@suse.com) | --- Comment #3 from Antonio Ojea ---

...

Did you intend to skip the change for "create_local_trace_uprobe()" in tracing-Fix-bad-use-of-igrab-in-trace_uprobe.c.patch?

hehe, that's far from my knowledge, I was just following the bpftrace tutorial. I've found this bug and reported it, feel free to close it if you consider is not worth fixing it. -- You are receiving this mail because: You are on the CC list for the bug.

bugzilla_noreply＠novell.com

11:40

New subject: [Bug 1146141] bpftrace: BUG: unable to handle kernel NULL pointer dereference at (null)

http://bugzilla.suse.com/show_bug.cgi?id=1146141 http://bugzilla.suse.com/show_bug.cgi?id=1146141#c4 --- Comment #4 from Gary Ching-Pang Lin --- (In reply to Antonio Ojea from comment #3)

...

...
Did you intend to skip the change for "create_local_trace_uprobe()" in tracing-Fix-bad-use-of-igrab-in-trace_uprobe.c.patch?

hehe, that's far from my knowledge, I was just following the bpftrace tutorial.

I've found this bug and reported it, feel free to close it if you consider is not worth fixing it.

Oh, you misunderstood the comment. I was asking my colleague :) -- You are receiving this mail because: You are on the CC list for the bug.