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* Call trace stops at static callback functions
@ 2019-06-22 12:40 Hauke Mehrtens
  2019-06-22 12:42 ` SGI-IP30 Carlo Pisani
  2019-06-24 18:10 ` Call trace stops at static callback functions Paul Burton
  0 siblings, 2 replies; 17+ messages in thread
From: Hauke Mehrtens @ 2019-06-22 12:40 UTC (permalink / raw)
  To: linux-mips

Hi,

When I add a WARN_ON(1) to trigger a backtrace into the static callback
function veth_newlink() in drivers/net/veth.c the backtrace stops at
this functions. When I remove the static from this function the
backtrace is looking like expected.

Call trace with static function:
[   30.686208] Call Trace:
[   30.686583] [<8010ca98>] show_stack+0x90/0x138
[   30.686953] [<8066ae80>] dump_stack+0x94/0xcc
[   30.687122] [<801307cc>] __warn+0x130/0x144
[   30.687293] [<80130898>] warn_slowpath_null+0x44/0x58
[   30.687545] [<c0023800>] 0xc0023800
[   30.687959] ---[ end trace df91e2ca103d67ec ]---

Call trace without static:
[   26.519328] Call Trace:
[   26.519648] [<8010ca98>] show_stack+0x90/0x138
[   26.520067] [<8066ae80>] dump_stack+0x94/0xcc
[   26.520282] [<801307cc>] __warn+0x130/0x144
[   26.520466] [<80130898>] warn_slowpath_null+0x44/0x58
[   26.520773] [<c0023800>] veth_newlink+0x64/0x1464 [veth]
[   26.521041] [<80541628>] __rtnl_newlink+0x5c8/0x790
[   26.521259] [<80541840>] rtnl_newlink+0x50/0x84
[   26.521456] [<8053b430>] rtnetlink_rcv_msg+0x340/0x3ec
[   26.521697] [<80571ba4>] netlink_rcv_skb+0xa0/0x150
[   26.521908] [<805712d8>] netlink_unicast+0x1c4/0x2b0
[   26.522121] [<805716ac>] netlink_sendmsg+0x2e8/0x3f8
[   26.522336] [<804fcf6c>] ___sys_sendmsg+0x144/0x2ac
[   26.522546] [<804fe22c>] __sys_sendmsg+0x4c/0x94
[   26.522748] [<80114a98>] syscall_common+0x34/0x58
[   26.523214] ---[ end trace 9a18b9fb2030ab29 ]---

This was done with kernel 5.2-rc5 build with OpenWrt (GCC 7.4) for Malta
24Kc big endian, the kernel did not contain any extra OpenWrt patches,
only the WARN_ON(1) was added to trigger this call trace.

Is it excepted that the call trace stops at such positions? It would be
really nice if it would go further to better interpret such call traces.

I used this command to call this function:
	ip link add veth0 type veth peer name veth1

I also saw this with kernel 4.9.

Hauke

^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2019-07-01 20:41 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-22 12:40 Call trace stops at static callback functions Hauke Mehrtens
2019-06-22 12:42 ` SGI-IP30 Carlo Pisani
2019-06-24 17:55   ` SGI-IP30 Paul Burton
2019-06-24 19:16     ` SGI-IP30 Maciej W. Rozycki
2019-06-25  8:59     ` SGI-IP30 Thomas Bogendoerfer
2019-06-26  4:23     ` SGI-IP30 Joshua Kinard
2019-06-26  5:49       ` SGI-IP30 Carlo Pisani
2019-07-01 19:27         ` SGI-IP30 Joshua Kinard
2019-06-27 20:38       ` SGI-IP30 Matt Turner
2019-06-27 22:29         ` SGI-IP30 Carlo Pisani
2019-06-28  8:27           ` SGI-IP30 Carlo Pisani
2019-07-01 18:31             ` SGI-IP30 Joshua Kinard
2019-07-01 18:36               ` SGI-IP30 Carlo Pisani
2019-07-01 20:29                 ` SGI-IP30 Joshua Kinard
2019-07-01 20:41                   ` SGI-IP30 Carlo Pisani
2019-06-28  9:46         ` SGI-IP30 Carlo Pisani
2019-06-24 18:10 ` Call trace stops at static callback functions Paul Burton

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