user/sven/linux.git/kernel/pid.c, branch v4.15.12

pid: Handle failure to allocate the first pid in a pid namespace

2017-12-24T03:00:09Z

With the replacement of the pid bitmap and hashtable with an idr in alloc_pid started occassionally failing when allocating the first pid in a pid namespace. Things were not completely reset resulting in the first allocated pid getting the number 2 (not 1). Which further resulted in ns->proc_mnt not getting set and eventually causing an oops in proc_flush_task. Oops: 0000 [#1] SMP CPU: 2 PID: 6743 Comm: trinity-c117 Not tainted 4.15.0-rc4-think+ #2 RIP: 0010:proc_flush_task+0x8e/0x1b0 RSP: 0018:ffffc9000bbffc40 EFLAGS: 00010286 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 00000000fffffffb RDX: 0000000000000000 RSI: ffffc9000bbffc50 RDI: 0000000000000000 RBP: ffffc9000bbffc63 R08: 0000000000000000 R09: 0000000000000002 R10: ffffc9000bbffb70 R11: ffffc9000bbffc64 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000003 R15: ffff8804c10d7840 FS: 00007f7cb8965700(0000) GS:ffff88050a200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000003e21ae003 CR4: 00000000001606e0 DR0: 00007fb1d6c22000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: ? release_task+0xaf/0x680 release_task+0xd2/0x680 ? wait_consider_task+0xb82/0xce0 wait_consider_task+0xbe9/0xce0 ? do_wait+0xe1/0x330 do_wait+0x151/0x330 kernel_wait4+0x8d/0x150 ? task_stopped_code+0x50/0x50 SYSC_wait4+0x95/0xa0 ? rcu_read_lock_sched_held+0x6c/0x80 ? syscall_trace_enter+0x2d7/0x340 ? do_syscall_64+0x60/0x210 do_syscall_64+0x60/0x210 entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7f7cb82603aa RSP: 002b:00007ffd60770bc8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 00007f7cb6cd4000 RCX: 00007f7cb82603aa RDX: 000000000000000b RSI: 00007ffd60770bd0 RDI: 0000000000007cca RBP: 0000000000007cca R08: 00007f7cb8965700 R09: 00007ffd607c7080 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd60770bd0 R14: 00007f7cb6cd4058 R15: 00000000cccccccd Code: c1 e2 04 44 8b 60 30 48 8b 40 38 44 8b 34 11 48 c7 c2 60 3a f5 81 44 89 e1 4c 8b 68 58 e8 4b b4 77 00 89 44 24 14 48 8d 74 24 10 <49> 8b 7d 00 e8 b9 6a f9 ff 48 85 c0 74 1a 48 89 c7 48 89 44 24 RIP: proc_flush_task+0x8e/0x1b0 RSP: ffffc9000bbffc40 CR2: 0000000000000000 ---[ end trace 53d67a6481059862 ]--- Improve the quality of the implementation by resetting the place to start allocating pids on failure to allocate the first pid. As improving the quality of the implementation is the goal remove the now unnecesarry disable_pid_allocations call when we fail to mount proc. Fixes: 95846ecf9dac ("pid: replace pid bitmap implementation with IDR API") Fixes: 8ef047aaaeb8 ("pid namespaces: make alloc_pid(), free_pid() and put_pid() work with struct upid") Reported-by: Dave Jones Signed-off-by: "Eric W. Biederman"

pid: remove pidhash

2017-11-18T00:10:04Z

pidhash is no longer required as all the information can be looked up from idr tree. nr_hashed represented the number of pids that had been hashed. Since, nr_hashed and PIDNS_HASH_ADDING are no longer relevant, it has been renamed to pid_allocated and PIDNS_ADDING respectively. [gs051095@gmail.com: v6] Link: http://lkml.kernel.org/r/1507760379-21662-3-git-send-email-gs051095@gmail.com Link: http://lkml.kernel.org/r/1507583624-22146-3-git-send-email-gs051095@gmail.com Signed-off-by: Gargi Sharma Reviewed-by: Rik van Riel Tested-by: Tony Luck [ia64] Cc: Julia Lawall Cc: Ingo Molnar Cc: Pavel Tatashin Cc: Kirill Tkhai Cc: Oleg Nesterov Cc: Eric W. Biederman Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid: replace pid bitmap implementation with IDR API

2017-11-18T00:10:03Z

Patch series "Replacing PID bitmap implementation with IDR API", v4. This series replaces kernel bitmap implementation of PID allocation with IDR API. These patches are written to simplify the kernel by replacing custom code with calls to generic code. The following are the stats for pid and pid_namespace object files before and after the replacement. There is a noteworthy change between the IDR and bitmap implementation. Before text data bss dec hex filename 8447 3894 64 12405 3075 kernel/pid.o After text data bss dec hex filename 3397 304 0 3701 e75 kernel/pid.o Before text data bss dec hex filename 5692 1842 192 7726 1e2e kernel/pid_namespace.o After text data bss dec hex filename 2854 216 16 3086 c0e kernel/pid_namespace.o The following are the stats for ps, pstree and calling readdir on /proc for 10,000 processes. ps: With IDR API With bitmap real 0m1.479s 0m2.319s user 0m0.070s 0m0.060s sys 0m0.289s 0m0.516s pstree: With IDR API With bitmap real 0m1.024s 0m1.794s user 0m0.348s 0m0.612s sys 0m0.184s 0m0.264s proc: With IDR API With bitmap real 0m0.059s 0m0.074s user 0m0.000s 0m0.004s sys 0m0.016s 0m0.016s This patch (of 2): Replace the current bitmap implementation for Process ID allocation. Functions that are no longer required, for example, free_pidmap(), alloc_pidmap(), etc. are removed. The rest of the functions are modified to use the IDR API. The change was made to make the PID allocation less complex by replacing custom code with calls to generic API. [gs051095@gmail.com: v6] Link: http://lkml.kernel.org/r/1507760379-21662-2-git-send-email-gs051095@gmail.com [avagin@openvz.org: restore the old behaviour of the ns_last_pid sysctl] Link: http://lkml.kernel.org/r/20171106183144.16368-1-avagin@openvz.org Link: http://lkml.kernel.org/r/1507583624-22146-2-git-send-email-gs051095@gmail.com Signed-off-by: Gargi Sharma Reviewed-by: Rik van Riel Acked-by: Oleg Nesterov Cc: Julia Lawall Cc: Ingo Molnar Cc: Pavel Tatashin Cc: Kirill Tkhai Cc: Eric W. Biederman Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pids: make task_tgid_nr_ns() safe

2017-08-21T19:47:31Z

This was reported many times, and this was even mentioned in commit 52ee2dfdd4f5 ("pids: refactor vnr/nr_ns helpers to make them safe") but somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() is not safe because task->group_leader points to nowhere after the exiting task passes exit_notify(), rcu_read_lock() can not help. We really need to change __unhash_process() to nullify group_leader, parent, and real_parent, but this needs some cleanups. Until then we can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and fix the problem. Reported-by: Troy Kensinger Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds

pid: kill pidhash_size in pidhash_init()

2017-08-02T23:34:46Z

After commit 3d375d78593c ("mm: update callers to use HASH_ZERO flag"), drop unused pidhash_size in pidhash_init(). Link: http://lkml.kernel.org/r/1500389267-49222-1-git-send-email-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: update callers to use HASH_ZERO flag

2017-07-06T23:24:33Z

Update dcache, inode, pid, mountpoint, and mount hash tables to use HASH_ZERO, and remove initialization after allocations. In case of places where HASH_EARLY was used such as in __pv_init_lock_hash the zeroed hash table was already assumed, because memblock zeroes the memory. CPU: SPARC M6, Memory: 7T Before fix: Dentry cache hash table entries: 1073741824 Inode-cache hash table entries: 536870912 Mount-cache hash table entries: 16777216 Mountpoint-cache hash table entries: 16777216 ftrace: allocating 20414 entries in 40 pages Total time: 11.798s After fix: Dentry cache hash table entries: 1073741824 Inode-cache hash table entries: 536870912 Mount-cache hash table entries: 16777216 Mountpoint-cache hash table entries: 16777216 ftrace: allocating 20414 entries in 40 pages Total time: 3.198s CPU: Intel Xeon E5-2630, Memory: 2.2T: Before fix: Dentry cache hash table entries: 536870912 Inode-cache hash table entries: 268435456 Mount-cache hash table entries: 8388608 Mountpoint-cache hash table entries: 8388608 CPU: Physical Processor ID: 0 Total time: 3.245s After fix: Dentry cache hash table entries: 536870912 Inode-cache hash table entries: 268435456 Mount-cache hash table entries: 8388608 Mountpoint-cache hash table entries: 8388608 CPU: Physical Processor ID: 0 Total time: 3.244s Link: http://lkml.kernel.org/r/1488432825-92126-4-git-send-email-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin Reviewed-by: Babu Moger Cc: David Miller Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()

2017-05-09T00:15:12Z

alloc_pidmap() advances pid_namespace::last_pid. When first pid allocation fails, then next created process will have pid 2 and pid_ns_prepare_proc() won't be called. So, pid_namespace::proc_mnt will never be initialized (not to mention that there won't be a child reaper). I saw crash stack of such case on kernel 3.10: BUG: unable to handle kernel NULL pointer dereference at (null) IP: proc_flush_task+0x8f/0x1b0 Call Trace: release_task+0x3f/0x490 wait_consider_task.part.10+0x7ff/0xb00 do_wait+0x11f/0x280 SyS_wait4+0x7d/0x110 We may fix this by restore of last_pid in 0 or by prohibiting of futher allocations. Since there was a similar issue in Oleg Nesterov's commit 314a8ad0f18a ("pidns: fix free_pid() to handle the first fork failure"). and it was fixed via prohibiting allocation, let's follow this way, and do the same. Link: http://lkml.kernel.org/r/149201021004.4863.6762095011554287922.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai Acked-by: Cyrill Gorcunov Cc: Andrei Vagin Cc: Andreas Gruenbacher Cc: Kees Cook Cc: Michael Kerrisk Cc: Al Viro Cc: Oleg Nesterov Cc: Paul Moore Cc: Eric Biederman Cc: Andy Lutomirski Cc: Ingo Molnar Cc: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:35Z

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

locking/atomic, kref: Add KREF_INIT()

2017-01-14T10:37:18Z

Since we need to change the implementation, stop exposing internals. Provide KREF_INIT() to allow static initialization of struct kref. Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

remove lots of IS_ERR_VALUE abuses

2016-05-27T22:26:11Z

Most users of IS_ERR_VALUE() in the kernel are wrong, as they pass an 'int' into a function that takes an 'unsigned long' argument. This happens to work because the type is sign-extended on 64-bit architectures before it gets converted into an unsigned type. However, anything that passes an 'unsigned short' or 'unsigned int' argument into IS_ERR_VALUE() is guaranteed to be broken, as are 8-bit integers and types that are wider than 'unsigned long'. Andrzej Hajda has already fixed a lot of the worst abusers that were causing actual bugs, but it would be nice to prevent any users that are not passing 'unsigned long' arguments. This patch changes all users of IS_ERR_VALUE() that I could find on 32-bit ARM randconfig builds and x86 allmodconfig. For the moment, this doesn't change the definition of IS_ERR_VALUE() because there are probably still architecture specific users elsewhere. Almost all the warnings I got are for files that are better off using 'if (err)' or 'if (err < 0)'. The only legitimate user I could find that we get a warning for is the (32-bit only) freescale fman driver, so I did not remove the IS_ERR_VALUE() there but changed the type to 'unsigned long'. For 9pfs, I just worked around one user whose calling conventions are so obscure that I did not dare change the behavior. I was using this definition for testing: #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \ unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO)) which ends up making all 16-bit or wider types work correctly with the most plausible interpretation of what IS_ERR_VALUE() was supposed to return according to its users, but also causes a compile-time warning for any users that do not pass an 'unsigned long' argument. I suggested this approach earlier this year, but back then we ended up deciding to just fix the users that are obviously broken. After the initial warning that caused me to get involved in the discussion (fs/gfs2/dir.c) showed up again in the mainline kernel, Linus asked me to send the whole thing again. [ Updated the 9p parts as per Al Viro - Linus ] Signed-off-by: Arnd Bergmann Cc: Andrzej Hajda Cc: Andrew Morton Link: https://lkml.org/lkml/2016/1/7/363 Link: https://lkml.org/lkml/2016/5/27/486 Acked-by: Srinivas Kandagatla # For nvmem part Signed-off-by: Linus Torvalds