Messages in this thread | | | Subject | Re: [PATCH RESEND v5 -tip] x86, dumpstack: Correct stack dump info when frame pointer is available | From | Peter Zijlstra <> | Date | Fri, 18 Mar 2011 10:40:33 +0100 |
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On Fri, 2011-03-18 at 11:40 +0900, Namhyung Kim wrote: > > Current stack dump code scans entire stack and check each entry > contains a pointer to kernel code. If CONFIG_FRAME_POINTER=y it > could mark whether the pointer is valid or not based on value of > the frame pointer. Invalid entries could be preceded by '?' sign. > > However this was not going to happen because scan start point was > always higher than the frame pointer so that they could not meet. > > Commit 9c0729dc8062 ("x86: Eliminate bp argument from the stack > tracing routines") delayed bp acquisition point, so the bp was > read in lower frame, thus all of the entries were marked invalid. > > This patch fixes this by reverting above commit while retaining > stack_frame() helper as suggested by Frederic Weisbecker. > End result looks like below: > > before: > [ 3.508329] Call Trace: > [ 3.508551] [<ffffffff814f35c9>] ? panic+0x91/0x199 > [ 3.508662] [<ffffffff814f3739>] ? printk+0x68/0x6a > [ 3.508770] [<ffffffff81a981b2>] ? mount_block_root+0x257/0x26e > [ 3.508876] [<ffffffff81a9821f>] ? mount_root+0x56/0x5a > [ 3.508975] [<ffffffff81a98393>] ? prepare_namespace+0x170/0x1a9 > [ 3.509216] [<ffffffff81a9772b>] ? kernel_init+0x1d2/0x1e2 > [ 3.509335] [<ffffffff81003894>] ? kernel_thread_helper+0x4/0x10 > [ 3.509442] [<ffffffff814f6880>] ? restore_args+0x0/0x30 > [ 3.509542] [<ffffffff81a97559>] ? kernel_init+0x0/0x1e2 > [ 3.509641] [<ffffffff81003890>] ? kernel_thread_helper+0x0/0x10 > > after: > [ 3.522991] Call Trace: > [ 3.523351] [<ffffffff814f35b9>] panic+0x91/0x199 > [ 3.523468] [<ffffffff814f3729>] ? printk+0x68/0x6a > [ 3.523576] [<ffffffff81a981b2>] mount_block_root+0x257/0x26e > [ 3.523681] [<ffffffff81a9821f>] mount_root+0x56/0x5a > [ 3.523780] [<ffffffff81a98393>] prepare_namespace+0x170/0x1a9 > [ 3.523885] [<ffffffff81a9772b>] kernel_init+0x1d2/0x1e2 > [ 3.523987] [<ffffffff81003894>] kernel_thread_helper+0x4/0x10 > [ 3.524228] [<ffffffff814f6880>] ? restore_args+0x0/0x30 > [ 3.524345] [<ffffffff81a97559>] ? kernel_init+0x0/0x1e2 > [ 3.524445] [<ffffffff81003890>] ? kernel_thread_helper+0x0/0x10 > > Signed-off-by: Namhyung Kim <namhyung@gmail.com> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Soren Sandmann <ssp@redhat.com> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Robert Richter <robert.richter@amd.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Ingo, _please_, pretty _please_ merge this? These wrecked unwinds drive me up the wall ;-)
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