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authorHeiko Carstens <heiko.carstens@de.ibm.com>2008-10-28 06:10:21 -0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-10-28 06:12:06 -0400
commit7f5a8ba6b0297ca941f43f8f5cbf0e5c8c4dd916 (patch)
tree8077f6d850ce26d8a33e505238c5b4848c5a9c6d /arch/s390/Kconfig
parent46e7951f9431b5e6bfbeb3044fdb4b522f58101c (diff)
[S390] No more 4kb stacks.
We got a stack overflow with a small stack configuration on a 32 bit system. It just looks like as 4kb isn't enough and too dangerous. So lets get rid of 4kb stacks on 32 bit. But one thing I completely dislike about the call trace below is that just for debugging or tracing purposes sprintf gets called (cio_start_key): /* process condition code */ sprintf(dbf_txt, "ccode:%d", ccode); CIO_TRACE_EVENT(4, dbf_txt); But maybe its just me who thinks that this could be done better. <4>Kernel stack overflow. <4>Modules linked in: dm_multipath sunrpc bonding qeth_l2 dm_mod qeth ccwgroup vmur <4>CPU: 1 Not tainted 2.6.27-30.x.20081015-s390default #1 <4>Process httpd (pid: 3807, task: 20ae2df8, ksp: 1666fb78) <4>Krnl PSW : 040c0000 8027098a (number+0xe/0x348) <4> R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 <4>Krnl GPRS: 00d43318 0027097c 1666f277 9666f270 <4> 00000000 00000000 0000000a ffffffff <4> 9666f270 1666f228 1666f277 1666f098 <4> 00000002 80270982 80271016 1666f098 <4>Krnl Code: 8027097e: f0340dd0a7f1 srp 3536(4,%r0),2033(%r10),4 <4> 80270984: 0f00 clcl %r0,%r0 <4> 80270986: a7840001 brc 8,80270988 <4> >8027098a: 18ef lr %r14,%r15 <4> 8027098c: a7faff68 ahi %r15,-152 <4> 80270990: 18bf lr %r11,%r15 <4> 80270992: 18a2 lr %r10,%r2 <4> 80270994: 1893 lr %r9,%r3 Modified calltrace with annotated stackframe size of each function: stackframe size | 0 304 vsnprintf+850 [0x271016] 1 72 sprintf+74 [0x271522] 2 56 cio_start_key+262 [0x2d4c16] 3 56 ccw_device_start_key+222 [0x2dfe92] 4 56 ccw_device_start+40 [0x2dff28] 5 48 raw3215_start_io+104 [0x30b0f8] 6 56 raw3215_write+494 [0x30ba0a] 7 40 con3215_write+68 [0x30bafc] 8 40 __call_console_drivers+146 [0x12b0fa] 9 32 _call_console_drivers+102 [0x12b192] 10 64 release_console_sem+268 [0x12b614] 11 168 vprintk+462 [0x12bca6] 12 72 printk+68 [0x12bfd0] 13 256 __print_symbol+50 [0x15a882] 14 56 __show_trace+162 [0x103d06] 15 32 show_trace+224 [0x103e70] 16 48 show_stack+152 [0x103f20] 17 56 dump_stack+126 [0x104612] 18 96 __alloc_pages_internal+592 [0x175004] 19 80 cache_alloc_refill+776 [0x196f3c] 20 40 __kmalloc+258 [0x1972ae] 21 40 __alloc_skb+94 [0x328086] 22 32 pskb_copy+50 [0x328252] 23 32 skb_realloc_headroom+110 [0x328a72] 24 104 qeth_l2_hard_start_xmit+378 [0x7803bfde] 25 56 dev_hard_start_xmit+450 [0x32ef6e] 26 56 __qdisc_run+390 [0x3425d6] 27 48 dev_queue_xmit+410 [0x331e06] 28 40 ip_finish_output+308 [0x354ac8] 29 56 ip_output+218 [0x355b6e] 30 24 ip_local_out+56 [0x354584] 31 120 ip_queue_xmit+300 [0x355cec] 32 96 tcp_transmit_skb+812 [0x367da8] 33 40 tcp_push_one+158 [0x369fda] 34 112 tcp_sendmsg+852 [0x35d5a0] 35 240 sock_sendmsg+164 [0x32035c] 36 56 kernel_sendmsg+86 [0x32064a] 37 88 sock_no_sendpage+98 [0x322b22] 38 104 tcp_sendpage+70 [0x35cc1e] 39 48 sock_sendpage+74 [0x31eb66] 40 64 pipe_to_sendpage+102 [0x1c4b2e] 41 64 __splice_from_pipe+120 [0x1c5340] 42 72 splice_from_pipe+90 [0x1c57e6] 43 56 generic_splice_sendpage+38 [0x1c5832] 44 48 do_splice_from+104 [0x1c4c38] 45 48 direct_splice_actor+52 [0x1c4c88] 46 80 splice_direct_to_actor+180 [0x1c4f80] 47 72 do_splice_direct+70 [0x1c5112] 48 64 do_sendfile+360 [0x19de18] 49 72 sys_sendfile64+126 [0x19df32] 50 336 sysc_do_restart+18 [0x111a1a] Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/Kconfig')
-rw-r--r--arch/s390/Kconfig14
1 files changed, 6 insertions, 8 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 5f5c29269fb1..8116a3328a19 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -241,19 +241,17 @@ config PACK_STACK
241 Say Y if you are unsure. 241 Say Y if you are unsure.
242 242
243config SMALL_STACK 243config SMALL_STACK
244 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb" 244 bool "Use 8kb for kernel stack instead of 16kb"
245 depends on PACK_STACK && !LOCKDEP 245 depends on PACK_STACK && 64BIT && !LOCKDEP
246 help 246 help
247 If you say Y here and the compiler supports the -mkernel-backchain 247 If you say Y here and the compiler supports the -mkernel-backchain
248 option the kernel will use a smaller kernel stack size. For 31 bit 248 option the kernel will use a smaller kernel stack size. The reduced
249 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb 249 size is 8kb instead of 16kb. This allows to run more threads on a
250 instead of 16kb. This allows to run more thread on a system and 250 system and reduces the pressure on the memory management for higher
251 reduces the pressure on the memory management for higher order 251 order page allocations.
252 page allocations.
253 252
254 Say N if you are unsure. 253 Say N if you are unsure.
255 254
256
257config CHECK_STACK 255config CHECK_STACK
258 bool "Detect kernel stack overflow" 256 bool "Detect kernel stack overflow"
259 help 257 help