Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756165AbZAIU3M (ORCPT ); Fri, 9 Jan 2009 15:29:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755118AbZAIU2y (ORCPT ); Fri, 9 Jan 2009 15:28:54 -0500 Received: from wf-out-1314.google.com ([209.85.200.175]:15086 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755115AbZAIU2w (ORCPT ); Fri, 9 Jan 2009 15:28:52 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:mime-version:content-type :content-transfer-encoding:content-disposition; b=AheTKO73ZWLDF+LIkTqE7bXsfOYPaCMEG6jhLvCkyaVb720xuOR6BdogHLeDvzr5Nd Wmob1hw/tMacxsZn/kA8zCta6WHtFEY6zC3rMmadfa6dSZNBcm4g8Y/zGHoLxsFrw/+9 iICls11ikVJfQdixuZCatP74LhBvupHPuKY38= Message-ID: <45a44e480901091228s59259c81tee1f7d4d4b19f49a@mail.gmail.com> Date: Sat, 10 Jan 2009 04:28:51 +0800 From: "Jaya Kumar" To: "Linux Kernel Mailing List" Subject: Oops in bluetooth on gumstix Cc: "David Howells" , "James Morris" MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 14309 Lines: 368 Hi folks, I pulled mainline to play with on my gumstix and encountered the following oops associated with bluetooth which was previously okay on 2.6.27. Here's the oops message: gumstix-custom-basix login: bnep0 (): not using net_device_ops yet Unable to handle kernel NULL pointer dereference at virtual address 00000150 pgd = c0004000 [00000150] *pgd=00000000 Internal error: Oops: f5 [#1] PREEMPT Modules linked in: CPU: 0 Not tainted (2.6.28gum-07487-gb7bc23a-dirty #3) PC is at set_dumpable+0x30/0xbc LR is at commit_creds+0x118/0x220 pc : [] lr : [] psr: 60000093 sp : c3b2def0 ip : c3b2df00 fp : c3b2defc r10: c3b2c000 r9 : c3a0e200 r8 : 00000000 r7 : 00000000 r6 : c38ac040 r5 : c0321618 r4 : c388bc80 r3 : 60000093 r2 : 60000093 r1 : 00000000 r0 : 00000000 Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user Control: 0000397f Table: a3b34000 DAC: 00000015 Process kbnepd bnep0 (pid: 782, stack limit = 0xc3b2c268) Stack: (0xc3b2def0 to 0xc3b2e000) dee0: c3b2df34 c3b2df00 c004f9c4 c0086bac df00: 00000100 00000000 ffffffff ffffffff fffffeff ffffffff c0041510 c3b2c000 df20: c3b2c000 c3a89b20 c3b2df4c c3b2df38 c00367b4 c004f8b8 c031cf60 c031cf60 df40: c3b2df74 c3b2df50 c00380a4 c00366c8 00000000 ffffffff ffffffff c3b2df7c df60: 00000000 00000000 c3b2dff4 c3b2df88 c024f54c c0037f84 c0301d48 c3a89800 df80: c3a89800 c34e11c0 c3b2dfac c3b2df98 c3a89800 c002d380 00000000 00000000 dfa0: 00000000 c3b2dfb0 c0020ea4 c002dfd8 00000000 c3a89b20 c024f514 c0037b24 dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 dfe0: 00000000 00000000 00000000 c3b2dff8 c0037b24 c024f520 00000000 00000000 Backtrace: [] (set_dumpable+0x0/0xbc) from [] (commit_creds+0x118/0x220) [] (commit_creds+0x0/0x220) from [] (reparent_to_kthreadd+0xf8/0x130) r6:c3a89b20 r5:c3b2c000 r4:c3b2c000 [] (reparent_to_kthreadd+0x0/0x130) from [] (daemonize+0x130/0x144) r4:c031cf60 [] (daemonize+0x0/0x144) from [] (bnep_session+0x38/0x6e8) r3:c34e11c0 r2:c3a89800 r1:c3a89800 r0:c0301d48 r5:00000000 r4:00000000 [] (bnep_session+0x0/0x6e8) from [] (do_exit+0x0/0x26c) Code: 1a000024 e10f2000 e3823080 e121f003 (e5903150) ---[ end trace 6b6196f25f5ef011 ]--- note: kbnepd bnep0[782] exited with preempt_count 1 I then bisected this and got the following result appended below. I haven't understood what is going on and whether it is a bluetooth issue or something else. I'll look into it more tomorrow but would appreciate any advice. Thanks, jaya $ after having pulled mainline $ git bisect bad $ git bisect good ab65387243f47a7bc11725f733c86bf27248b326 $ git-bisect bad d84f4f992cbd76e8f39c488cf0c5d123843923b1 is first bad commit commit d84f4f992cbd76e8f39c488cf0c5d123843923b1 Author: David Howells Date: Fri Nov 14 10:39:23 2008 +1100 CRED: Inaugurate COW credentials Inaugurate copy-on-write credentials management. This uses RCU to manage the credentials pointer in the task_struct with respect to accesses by other tasks. A process may only modify its own credentials, and so does not need locking to access or modify its own credentials. A mutex (cred_replace_mutex) is added to the task_struct to control the effect of PTRACE_ATTACHED on credential calculations, particularly with respect to execve(). With this patch, the contents of an active credentials struct may not be changed directly; rather a new set of credentials must be prepared, modified and committed using something like the following sequence of events: struct cred *new = prepare_creds(); int ret = blah(new); if (ret < 0) { abort_creds(new); return ret; } return commit_creds(new); There are some exceptions to this rule: the keyrings pointed to by the active credentials may be instantiated - keyrings violate the COW rule as managing COW keyrings is tricky, given that it is possible for a task to directly alter the keys in a keyring in use by another task. To help enforce this, various pointers to sets of credentials, such as those in the task_struct, are declared const. The purpose of this is compile-time discouragement of altering credentials through those pointers. Once a set of credentials has been made public through one of these pointers, it may not be modified, except under special circumstances: (1) Its reference count may incremented and decremented. (2) The keyrings to which it points may be modified, but not replaced. The only safe way to modify anything else is to create a replacement and commit using the functions described in Documentation/credentials.txt (which will be added by a later patch). This patch and the preceding patches have been tested with the LTP SELinux testsuite. This patch makes several logical sets of alteration: (1) execve(). This now prepares and commits credentials in various places in the security code rather than altering the current creds directly. (2) Temporary credential overrides. do_coredump() and sys_faccessat() now prepare their own credentials and temporarily override the ones currently on the acting thread, whilst preventing interference from other threads by holding cred_replace_mutex on the thread being dumped. This will be replaced in a future patch by something that hands down the credentials directly to the functions being called, rather than altering the task's objective credentials. (3) LSM interface. A number of functions have been changed, added or removed: (*) security_capset_check(), ->capset_check() (*) security_capset_set(), ->capset_set() Removed in favour of security_capset(). (*) security_capset(), ->capset() New. This is passed a pointer to the new creds, a pointer to the old creds and the proposed capability sets. It should fill in the new creds or return an error. All pointers, barring the pointer to the new creds, are now const. (*) security_bprm_apply_creds(), ->bprm_apply_creds() Changed; now returns a value, which will cause the process to be killed if it's an error. (*) security_task_alloc(), ->task_alloc_security() Removed in favour of security_prepare_creds(). (*) security_cred_free(), ->cred_free() New. Free security data attached to cred->security. (*) security_prepare_creds(), ->cred_prepare() New. Duplicate any security data attached to cred->security. (*) security_commit_creds(), ->cred_commit() New. Apply any security effects for the upcoming installation of new security by commit_creds(). (*) security_task_post_setuid(), ->task_post_setuid() Removed in favour of security_task_fix_setuid(). (*) security_task_fix_setuid(), ->task_fix_setuid() Fix up the proposed new credentials for setuid(). This is used by cap_set_fix_setuid() to implicitly adjust capabilities in line with setuid() changes. Changes are made to the new credentials, rather than the task itself as in security_task_post_setuid(). (*) security_task_reparent_to_init(), ->task_reparent_to_init() Removed. Instead the task being reparented to init is referred directly to init's credentials. NOTE! This results in the loss of some state: SELinux's osid no longer records the sid of the thread that forked it. (*) security_key_alloc(), ->key_alloc() (*) security_key_permission(), ->key_permission() Changed. These now take cred pointers rather than task pointers to refer to the security context. (4) sys_capset(). This has been simplified and uses less locking. The LSM functions it calls have been merged. (5) reparent_to_kthreadd(). This gives the current thread the same credentials as init by simply using commit_thread() to point that way. (6) __sigqueue_alloc() and switch_uid() __sigqueue_alloc() can't stop the target task from changing its creds beneath it, so this function gets a reference to the currently applicable user_struct which it then passes into the sigqueue struct it returns if successful. switch_uid() is now called from commit_creds(), and possibly should be folded into that. commit_creds() should take care of protecting __sigqueue_alloc(). (7) [sg]et[ug]id() and co and [sg]et_current_groups. The set functions now all use prepare_creds(), commit_creds() and abort_creds() to build and check a new set of credentials before applying it. security_task_set[ug]id() is called inside the prepared section. This guarantees that nothing else will affect the creds until we've finished. The calling of set_dumpable() has been moved into commit_creds(). Much of the functionality of set_user() has been moved into commit_creds(). The get functions all simply access the data directly. (8) security_task_prctl() and cap_task_prctl(). security_task_prctl() has been modified to return -ENOSYS if it doesn't want to handle a function, or otherwise return the return value directly rather than through an argument. Additionally, cap_task_prctl() now prepares a new set of credentials, even if it doesn't end up using it. (9) Keyrings. A number of changes have been made to the keyrings code: (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have all been dropped and built in to the credentials functions directly. They may want separating out again later. (b) key_alloc() and search_process_keyrings() now take a cred pointer rather than a task pointer to specify the security context. (c) copy_creds() gives a new thread within the same thread group a new thread keyring if its parent had one, otherwise it discards the thread keyring. (d) The authorisation key now points directly to the credentials to extend the search into rather pointing to the task that carries them. (e) Installing thread, process or session keyrings causes a new set of credentials to be created, even though it's not strictly necessary for process or session keyrings (they're shared). (10) Usermode helper. The usermode helper code now carries a cred struct pointer in its subprocess_info struct instead of a new session keyring pointer. This set of credentials is derived from init_cred and installed on the new process after it has been cloned. call_usermodehelper_setup() allocates the new credentials and call_usermodehelper_freeinfo() discards them if they haven't been used. A special cred function (prepare_usermodeinfo_creds()) is provided specifically for call_usermodehelper_setup() to call. call_usermodehelper_setkeys() adjusts the credentials to sport the supplied keyring as the new session keyring. (11) SELinux. SELinux has a number of changes, in addition to those to support the LSM interface changes mentioned above: (a) selinux_setprocattr() no longer does its check for whether the current ptracer can access processes with the new SID inside the lock that covers getting the ptracer's SID. Whilst this lock ensures that the check is done with the ptracer pinned, the result is only valid until the lock is released, so there's no point doing it inside the lock. (12) is_single_threaded(). This function has been extracted from selinux_setprocattr() and put into a file of its own in the lib/ directory as join_session_keyring() now wants to use it too. The code in SELinux just checked to see whether a task shared mm_structs with other tasks (CLONE_VM), but that isn't good enough. We really want to know if they're part of the same thread group (CLONE_THREAD). (13) nfsd. The NFS server daemon now has to use the COW credentials to set the credentials it is going to use. It really needs to pass the credentials down to the functions it calls, but it can't do that until other patches in this series have been applied. Signed-off-by: David Howells Acked-by: James Morris Signed-off-by: James Morris :040000 040000 54679388642b328ef9f83053dda93cf7b384c1a1 1e05b20df131aaefbf47477df23a43372d49b892 M fs :040000 040000 46cecb343e899eaa0e7f3f02b5cc9fb47cb479bc c481b615af67d685bc43cef14b7e65648804e5b9 M include :040000 040000 1d6d049a7c8b44de21955be33aa21601ffee4293 ca03e5d9b0fdbc36ef8414c8204c5f4028fc2450 M init :040000 040000 937d58d5ab517eb27639a1dbabd82badc22e1dd8 6a6c8ebb9b52adfb46a3dad4199f45255954ae4e M kernel :040000 040000 0be63d6096b307a9a7310cd4eeb127a22840522e 7a36c5d69683a45f541d03f288776591643218e5 M lib :040000 040000 999a868ad972b27cfca54865633b923530b3c870 e001b88d115944ba794ea0baf7d79332cd888feb M net :040000 040000 c1bfa8c31e4c2a0c24be160925b79090b5d40ac6 4ba0ca62e135723401853a45e7b97e4ab667b6fe M security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/