fs: warn in case userspace lied about modprobe return
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PATCH v2 1/1 fs: warn in case userspace lied about modprobe return
kmod <= v19 was broken -- it could return 0 to modprobe calls, incorrectly assuming that a kernel module was built-in, whereas in reality the module was just forming in the kernel. The reason for this is an incorrect userspace heuristics. A userspace kmod fix is available for it [0], however should userspace break again we could go on with an failed get_fs_type() which is hard to debug as the request_module() is detected as returning 0. The first suspect would be that there is something worth with the kernel's module loader and obviously in this case that is not the issue.
Since these issues are painful to debug complain when we know userspace has outright lied to us.
---
This v2 addresses the ordering issue Jessica pointed out.
fs/filesystems.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
fs/filesystems.c +3 -1
@@ -275,8 +275,10 @@ struct file_system_type *get_fs_type(const char *name)int len = dot ? dot - name :strlen (name); fs =__get_fs_type (name, len); -if (!fs && (request_module ("fs-%.*s" , len, name) ==0 )) +if (!fs && (request_module ("fs-%.*s" , len, name) ==0 )) { fs =__get_fs_type (name, len); +WARN_ONCE (!fs,"request_module fs-%.*s succeeded, but still no fs?\n" , len, name); + }if (dot && fs && !(fs->fs_flags &FS_HAS_SUBTYPE )) {put_filesystem (fs);
Signature · 1 line
2.11.0
Quoted 10 lines · Luis R. Rodriguez
kmod <= v19 was broken -- it could return 0 to modprobe calls, incorrectly assuming that a kernel module was built-in, whereas in reality the module was just forming in the kernel. The reason for this is an incorrect userspace heuristics. A userspace kmod fix is available for it [0], however should userspace break again we could go on with an failed
get_fs_type()which is hard to debug as therequest_module()is detected as returning 0. The first suspect would be that there is something worth with the kernel's module loader and obviously in this case that is not the issue.
Quoted 8 lines
Since these issues are painful to debug complain when we know userspace has outright lied to us.
Suggested-by Rusty Russell <[email protected]>Cc Jessica Yu <[email protected]>Signed-off-by Luis R. Rodriguez <[email protected]>
*poke* Al?
Luis
Quoted 14 lines · Luis R. Rodriguez
Quoted 13 lines · Luis R. Rodriguez
kmod <= v19 was broken -- it could return 0 to modprobe calls, incorrectly assuming that a kernel module was built-in, whereas in reality the module was just forming in the kernel. The reason for this is an incorrect userspace heuristics. A userspace kmod fix is available for it [0], however should userspace break again we could go on with an failed
get_fs_type()which is hard to debug as therequest_module()is detected as returning 0. The first suspect would be that there is something worth with the kernel's module loader and obviously in this case that is not the issue.Since these issues are painful to debug complain when we know userspace has outright lied to us.
Quoted 7 lines
Quoted 5 lines
Suggested-by Rusty Russell <[email protected]>Cc Jessica Yu <[email protected]>Signed-off-by Luis R. Rodriguez <[email protected]>*poke* Al?
Will bounce to the default tree maintainer, Andrew :)
Luis