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authorSakari Ailus <sakari.ailus@iki.fi>2011-06-26 19:36:46 +0300
committerRusty Russell <rusty@rustcorp.com.au>2011-07-22 14:39:48 +0930
commite0377e25206328998d036cafddcd00a7c3252e3e (patch)
tree6cd94c5510d439b8af4ae0ae85deeab8c1c5bdd8 /Documentation/virtual/lguest
parent02f8c6aee8df3cdc935e9bdd4f2d020306035dbe (diff)
lguest: Do not exit on non-fatal errors
Do not exit on some non-fatal errors: - writev() fails in net_output(). The result is a lost packet or packets. - writev() fails in console_output(). The result is partially lost console output. - readv() fails in net_input(). The result is a lost packet or packets. Rather than bringing the guest down, this patch ignores e.g. an allocation failure on the host side. Example: lguest: page allocation failure. order:4, mode:0x4d0 Pid: 4045, comm: lguest Tainted: G W 2.6.36 #1 Call Trace: [<c138d614>] ? printk+0x18/0x1c [<c106a4e2>] __alloc_pages_nodemask+0x4d2/0x570 [<c1087954>] cache_alloc_refill+0x2a4/0x4d0 [<c1305149>] ? __netif_receive_skb+0x189/0x270 [<c1087c5a>] __kmalloc+0xda/0xf0 [<c12fffa5>] __alloc_skb+0x55/0x100 [<c1305519>] ? net_rx_action+0x79/0x100 [<c12fafed>] sock_alloc_send_pskb+0x18d/0x280 [<c11fda25>] ? _copy_from_user+0x35/0x130 [<c13010b6>] ? memcpy_fromiovecend+0x56/0x80 [<c12a74dc>] tun_chr_aio_write+0x1cc/0x500 [<c108a125>] do_sync_readv_writev+0x95/0xd0 [<c11fda25>] ? _copy_from_user+0x35/0x130 [<c1089fa8>] ? rw_copy_check_uvector+0x58/0x100 [<c108a7bc>] do_readv_writev+0x9c/0x1d0 [<c12a7310>] ? tun_chr_aio_write+0x0/0x500 [<c108a93a>] vfs_writev+0x4a/0x60 [<c108aa21>] sys_writev+0x41/0x80 [<c138f061>] syscall_call+0x7/0xb Mem-Info: DMA per-cpu: CPU 0: hi: 0, btch: 1 usd: 0 Normal per-cpu: CPU 0: hi: 186, btch: 31 usd: 0 HighMem per-cpu: CPU 0: hi: 186, btch: 31 usd: 0 active_anon:134651 inactive_anon:50543 isolated_anon:0 active_file:96881 inactive_file:132007 isolated_file:0 unevictable:0 dirty:3 writeback:0 unstable:0 free:91374 slab_reclaimable:6300 slab_unreclaimable:2802 mapped:2281 shmem:9 pagetables:330 bounce:0 DMA free:3524kB min:64kB low:80kB high:96kB active_anon:0kB inactive_anon:8kB active_file:8760kB inactive_file:2760kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15868kB mlocked:0kB dirty:0kB writeback:0kB mapped:16kB shmem:0kB slab_reclaimable:88kB slab_unreclaimable:148kB kernel_stack:40kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 865 2016 2016 Normal free:150100kB min:3728kB low:4660kB high:5592kB active_anon:6224kB inactive_anon:15772kB active_file:324084kB inactive_file:325944kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:885944kB mlocked:0kB dirty:12kB writeback:0kB mapped:1520kB shmem:0kB slab_reclaimable:25112kB slab_unreclaimable:11060kB kernel_stack:1888kB pagetables:1320kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 9207 9207 HighMem free:211872kB min:512kB low:1752kB high:2992kB active_anon:532380kB inactive_anon:186392kB active_file:54680kB inactive_file:199324kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:1178504kB mlocked:0kB dirty:0kB writeback:0kB mapped:7588kB shmem:36kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 DMA: 3*4kB 65*8kB 35*16kB 18*32kB 11*64kB 9*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3524kB Normal: 35981*4kB 344*8kB 158*16kB 28*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 150100kB HighMem: 5732*4kB 5462*8kB 2826*16kB 1598*32kB 84*64kB 10*128kB 7*256kB 1*512kB 1*1024kB 1*2048kB 9*4096kB = 211872kB 231237 total pagecache pages 2340 pages in swap cache Swap cache stats: add 160060, delete 157720, find 189017/194106 Free swap = 4179840kB Total swap = 4194300kB 524271 pages RAM 296946 pages HighMem 5668 pages reserved 867664 pages shared 82155 pages non-shared Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'Documentation/virtual/lguest')
-rw-r--r--Documentation/virtual/lguest/lguest.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/Documentation/virtual/lguest/lguest.c b/Documentation/virtual/lguest/lguest.c
index cd9d6af61d07..e3b9bb7a644a 100644
--- a/Documentation/virtual/lguest/lguest.c
+++ b/Documentation/virtual/lguest/lguest.c
@@ -861,8 +861,10 @@ static void console_output(struct virtqueue *vq)
/* writev can return a partial write, so we loop here. */
while (!iov_empty(iov, out)) {
int len = writev(STDOUT_FILENO, iov, out);
- if (len <= 0)
- err(1, "Write to stdout gave %i", len);
+ if (len <= 0) {
+ warn("Write to stdout gave %i (%d)", len, errno);
+ break;
+ }
iov_consume(iov, out, len);
}
@@ -898,7 +900,7 @@ static void net_output(struct virtqueue *vq)
* same format: what a coincidence!
*/
if (writev(net_info->tunfd, iov, out) < 0)
- errx(1, "Write to tun failed?");
+ warnx("Write to tun failed (%d)?", errno);
/*
* Done with that one; wait_for_vq_desc() will send the interrupt if
@@ -955,7 +957,7 @@ static void net_input(struct virtqueue *vq)
*/
len = readv(net_info->tunfd, iov, in);
if (len <= 0)
- err(1, "Failed to read from tun.");
+ warn("Failed to read from tun (%d).", errno);
/*
* Mark that packet buffer as used, but don't interrupt here. We want