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  • Heiko Carstens's avatar
    [S390] No more 4kb stacks. · 7f5a8ba6
    Heiko Carstens authored
    
    
    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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    7f5a8ba6