diff options
| author | Brian Behlendorf <[email protected]> | 2012-12-18 17:02:27 -0800 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2012-12-19 09:06:35 -0800 |
| commit | 034f1b331e2c152e8e8954d715fa9a84f7b48d64 (patch) | |
| tree | a7101b1b0e87624f60dc88ffa34c6993e6f31c23 /module/spl/spl-generic.c | |
| parent | 30196bfd42567a9bc3fccac8650dc2cd9f0f7c0a (diff) | |
Fix spl_kmem_init_kallsyms_lookup() panic
Due to I/O buffering the helper may return successfully before
the proc handler has a chance to execute. To catch this case
wait up to 1 second to verify spl_kallsyms_lookup_name_fn was
updated to a non SYMBOL_POISON value.
Signed-off-by: Brian Behlendorf <[email protected]>
Closes zfsonlinux/zfs#699
Closes zfsonlinux/zfs#859
Diffstat (limited to 'module/spl/spl-generic.c')
| -rw-r--r-- | module/spl/spl-generic.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/module/spl/spl-generic.c b/module/spl/spl-generic.c index cc2766452..22ea50781 100644 --- a/module/spl/spl-generic.c +++ b/module/spl/spl-generic.c @@ -64,6 +64,7 @@ proc_t p0 = { 0 }; EXPORT_SYMBOL(p0); #ifndef HAVE_KALLSYMS_LOOKUP_NAME +DECLARE_WAIT_QUEUE_HEAD(spl_kallsyms_lookup_name_waitq); kallsyms_lookup_name_t spl_kallsyms_lookup_name_fn = SYMBOL_POISON; #endif @@ -607,6 +608,24 @@ set_kallsyms_lookup_name(void) int rc; rc = call_usermodehelper(argv[0], argv, envp, 1); + + /* + * Due to I/O buffering the helper may return successfully before + * the proc handler has a chance to execute. To catch this case + * wait up to 1 second to verify spl_kallsyms_lookup_name_fn was + * updated to a non SYMBOL_POISON value. + */ + if (rc == 0) { + rc = wait_event_timeout(spl_kallsyms_lookup_name_waitq, + spl_kallsyms_lookup_name_fn != SYMBOL_POISON, HZ); + if (rc == 0) + rc = -ETIMEDOUT; + else if (spl_kallsyms_lookup_name_fn == SYMBOL_POISON) + rc = -EFAULT; + else + rc = 0; + } + if (rc) printk("SPL: Failed user helper '%s %s %s', rc = %d\n", argv[0], argv[1], argv[2], rc); |