user/sven/linux.git/kernel, branch v5.12.19

kprobe/static_call: Restore missing static_call_text_reserved()

2021-07-20T14:02:27Z

[ Upstream commit fa68bd09fc62240a383c0c601d3349c47db10c34 ] Restore two hunks from commit: 6333e8f73b83 ("static_call: Avoid kprobes on inline static_call()s") that went walkabout in a Git merge commit. Fixes: 76d4acf22b48 ("Merge tag 'perf-kprobes-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20210628113045.167127609@infradead.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

static_call: Fix static_call_text_reserved() vs __init

2021-07-20T14:02:27Z

[ Upstream commit 2bee6d16e4379326b1eea454e68c98b17456769e ] It turns out that static_call_text_reserved() was reporting __init text as being reserved past the time when the __init text was freed and re-used. This is mostly harmless and will at worst result in refusing a kprobe. Fixes: 6333e8f73b83 ("static_call: Avoid kprobes on inline static_call()s") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20210628113045.106211657@infradead.org Signed-off-by: Sasha Levin

jump_label: Fix jump_label_text_reserved() vs __init

2021-07-20T14:02:27Z

[ Upstream commit 9e667624c291753b8a5128f620f493d0b5226063 ] It turns out that jump_label_text_reserved() was reporting __init text as being reserved past the time when the __init text was freed and re-used. For a long time, this resulted in, at worst, not being able to kprobe text that happened to land at the re-used address. However a recent commit e7bf1ba97afd ("jump_label, x86: Emit short JMP") made it a fatal mistake because it now needs to read the instruction in order to determine the conflict -- an instruction that's no longer there. Fixes: 4c3ef6d79328 ("jump label: Add jump_label_text_reserved() to reserve jump points") Reported-by: kernel test robot Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20210628113045.045141693@infradead.org Signed-off-by: Sasha Levin

sched/uclamp: Ignore max aggregation if rq is idle

2021-07-20T14:02:27Z

[ Upstream commit 3e1493f46390618ea78607cb30c58fc19e2a5035 ] When a task wakes up on an idle rq, uclamp_rq_util_with() would max aggregate with rq value. But since there is no task enqueued yet, the values are stale based on the last task that was running. When the new task actually wakes up and enqueued, then the rq uclamp values should reflect that of the newly woken up task effective uclamp values. This is a problem particularly for uclamp_max because it default to 1024. If a task p with uclamp_max = 512 wakes up, then max aggregation would ignore the capping that should apply when this task is enqueued, which is wrong. Fix that by ignoring max aggregation if the rq is idle since in that case the effective uclamp value of the rq will be the ones of the task that will wake up. Fixes: 9d20ad7dfc9a ("sched/uclamp: Add uclamp_util_with()") Signed-off-by: Xuewen Yan Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider [qias: Changelog] Reviewed-by: Qais Yousef Link: https://lore.kernel.org/r/20210630141204.8197-1-xuewen.yan94@gmail.com Signed-off-by: Sasha Levin

module: correctly exit module_kallsyms_on_each_symbol when fn() != 0

2021-07-20T14:02:17Z

[ Upstream commit 2c0f0f3639562d6e38ee9705303c6457c4936eac ] Commit 013c1667cf78 ("kallsyms: refactor {,module_}kallsyms_on_each_symbol") replaced the return inside the nested loop with a break, changing the semantics of the function: the break only exits the innermost loop, so the code continues iterating the symbols of the next module instead of exiting. Fixes: 013c1667cf78 ("kallsyms: refactor {,module_}kallsyms_on_each_symbol") Reviewed-by: Petr Mladek Reviewed-by: Miroslav Benes Signed-off-by: Jon Mediero Signed-off-by: Jessica Yu Signed-off-by: Sasha Levin

rcu: Reject RCU_LOCKDEP_WARN() false positives

2021-07-20T14:02:03Z

[ Upstream commit 3066820034b5dd4e89bd74a7739c51c2d6f5e554 ] If another lockdep report runs concurrently with an RCU lockdep report from RCU_LOCKDEP_WARN(), the following sequence of events can occur: 1. debug_lockdep_rcu_enabled() sees that lockdep is enabled when called from (say) synchronize_rcu(). 2. Lockdep is disabled by a concurrent lockdep report. 3. debug_lockdep_rcu_enabled() evaluates its lockdep-expression argument, for example, lock_is_held(&rcu_bh_lock_map). 4. Because lockdep is now disabled, lock_is_held() plays it safe and returns the constant 1. 5. But in this case, the constant 1 is not safe, because invoking synchronize_rcu() under rcu_read_lock_bh() is disallowed. 6. debug_lockdep_rcu_enabled() wrongly invokes lockdep_rcu_suspicious(), resulting in a false-positive splat. This commit therefore changes RCU_LOCKDEP_WARN() to check debug_lockdep_rcu_enabled() after checking the lockdep expression, so that any "safe" returns from lock_is_held() are rejected by debug_lockdep_rcu_enabled(). This requires memory ordering, which is supplied by READ_ONCE(debug_locks). The resulting volatile accesses prevent the compiler from reordering and the fact that only one variable is being accessed prevents the underlying hardware from reordering. The combination works for IA64, which can reorder reads to the same location, but this is defeated by the volatile accesses, which compile to load instructions that provide ordering. Reported-by: syzbot+dde0cc33951735441301@syzkaller.appspotmail.com Reported-by: Matthew Wilcox Reported-by: syzbot+88e4f02896967fe1ab0d@syzkaller.appspotmail.com Reported-by: Thomas Gleixner Suggested-by: Boqun Feng Reviewed-by: Boqun Feng Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin

srcu: Fix broken node geometry after early ssp init

2021-07-20T14:02:03Z

[ Upstream commit b5befe842e6612cf894cf4a199924ee872d8b7d8 ] An srcu_struct structure that is initialized before rcu_init_geometry() will have its srcu_node hierarchy based on CONFIG_NR_CPUS. Once rcu_init_geometry() is called, this hierarchy is compressed as needed for the actual maximum number of CPUs for this system. Later on, that srcu_struct structure is confused, sometimes referring to its initial CONFIG_NR_CPUS-based hierarchy, and sometimes instead to the new num_possible_cpus() hierarchy. For example, each of its ->mynode fields continues to reference the original leaf rcu_node structures, some of which might no longer exist. On the other hand, srcu_for_each_node_breadth_first() traverses to the new node hierarchy. There are at least two bad possible outcomes to this: 1) a) A callback enqueued early on an srcu_data structure (call it *sdp) is recorded pending on sdp->mynode->srcu_data_have_cbs in srcu_funnel_gp_start() with sdp->mynode pointing to a deep leaf (say 3 levels). b) The grace period ends after rcu_init_geometry() shrinks the nodes level to a single one. srcu_gp_end() walks through the new srcu_node hierarchy without ever reaching the old leaves so the callback is never executed. This is easily reproduced on an 8 CPUs machine with CONFIG_NR_CPUS >= 32 and "rcupdate.rcu_self_test=1". The srcu_barrier() after early tests verification never completes and the boot hangs: [ 5413.141029] INFO: task swapper/0:1 blocked for more than 4915 seconds. [ 5413.147564] Not tainted 5.12.0-rc4+ #28 [ 5413.151927] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 5413.159753] task:swapper/0 state:D stack: 0 pid: 1 ppid: 0 flags:0x00004000 [ 5413.168099] Call Trace: [ 5413.170555] __schedule+0x36c/0x930 [ 5413.174057] ? wait_for_completion+0x88/0x110 [ 5413.178423] schedule+0x46/0xf0 [ 5413.181575] schedule_timeout+0x284/0x380 [ 5413.185591] ? wait_for_completion+0x88/0x110 [ 5413.189957] ? mark_held_locks+0x61/0x80 [ 5413.193882] ? mark_held_locks+0x61/0x80 [ 5413.197809] ? _raw_spin_unlock_irq+0x24/0x50 [ 5413.202173] ? wait_for_completion+0x88/0x110 [ 5413.206535] wait_for_completion+0xb4/0x110 [ 5413.210724] ? srcu_torture_stats_print+0x110/0x110 [ 5413.215610] srcu_barrier+0x187/0x200 [ 5413.219277] ? rcu_tasks_verify_self_tests+0x50/0x50 [ 5413.224244] ? rdinit_setup+0x2b/0x2b [ 5413.227907] rcu_verify_early_boot_tests+0x2d/0x40 [ 5413.232700] do_one_initcall+0x63/0x310 [ 5413.236541] ? rdinit_setup+0x2b/0x2b [ 5413.240207] ? rcu_read_lock_sched_held+0x52/0x80 [ 5413.244912] kernel_init_freeable+0x253/0x28f [ 5413.249273] ? rest_init+0x250/0x250 [ 5413.252846] kernel_init+0xa/0x110 [ 5413.256257] ret_from_fork+0x22/0x30 2) An srcu_struct structure that is initialized before rcu_init_geometry() and used afterward will always have stale rdp->mynode references, resulting in callbacks to be missed in srcu_gp_end(), just like in the previous scenario. This commit therefore causes init_srcu_struct_nodes to initialize the geometry, if needed. This ensures that the srcu_node hierarchy is properly built and distributed from the get-go. Suggested-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Boqun Feng Cc: Lai Jiangshan Cc: Neeraj Upadhyay Cc: Josh Triplett Cc: Joel Fernandes Cc: Uladzislau Rezki Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin

cgroup: verify that source is a string

2021-07-20T14:02:01Z

commit 3b0462726e7ef281c35a7a4ae33e93ee2bc9975b upstream. The following sequence can be used to trigger a UAF: int fscontext_fd = fsopen("cgroup"); int fd_null = open("/dev/null, O_RDONLY); int fsconfig(fscontext_fd, FSCONFIG_SET_FD, "source", fd_null); close_range(3, ~0U, 0); The cgroup v1 specific fs parser expects a string for the "source" parameter. However, it is perfectly legitimate to e.g. specify a file descriptor for the "source" parameter. The fs parser doesn't know what a filesystem allows there. So it's a bug to assume that "source" is always of type fs_value_is_string when it can reasonably also be fs_value_is_file. This assumption in the cgroup code causes a UAF because struct fs_parameter uses a union for the actual value. Access to that union is guarded by the param->type member. Since the cgroup paramter parser didn't check param->type but unconditionally moved param->string into fc->source a close on the fscontext_fd would trigger a UAF during put_fs_context() which frees fc->source thereby freeing the file stashed in param->file causing a UAF during a close of the fd_null. Fix this by verifying that param->type is actually a string and report an error if not. In follow up patches I'll add a new generic helper that can be used here and by other filesystems instead of this error-prone copy-pasta fix. But fixing it in here first makes backporting a it to stable a lot easier. Fixes: 8d2451f4994f ("cgroup1: switch to option-by-option parsing") Reported-by: syzbot+283ce5a46486d6acdbaf@syzkaller.appspotmail.com Cc: Christoph Hellwig Cc: Alexander Viro Cc: Dmitry Vyukov Cc: Cc: syzkaller-bugs Signed-off-by: Christian Brauner Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

tracing: Do not reference char * as a string in histograms

2021-07-20T14:02:01Z

commit 704adfb5a9978462cd861f170201ae2b5e3d3a80 upstream. The histogram logic was allowing events with char * pointers to be used as normal strings. But it was easy to crash the kernel with: # echo 'hist:keys=filename' > events/syscalls/sys_enter_openat/trigger And open some files, and boom! BUG: unable to handle page fault for address: 00007f2ced0c3280 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1173fa067 P4D 1173fa067 PUD 1171b6067 PMD 1171dd067 PTE 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ #61 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016 RIP: 0010:strlen+0x0/0x20 Code: f6 82 80 2a 0b a9 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2a 0b a9 20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 RSP: 0018:ffffbdbf81567b50 EFLAGS: 00010246 RAX: 0000000000000003 RBX: ffff93815cdb3800 RCX: ffff9382401a22d0 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 00007f2ced0c3280 RBP: 0000000000000100 R08: ffff9382409ff074 R09: ffffbdbf81567c98 R10: ffff9382409ff074 R11: 0000000000000000 R12: ffff9382409ff074 R13: 0000000000000001 R14: ffff93815a744f00 R15: 00007f2ced0c3280 FS: 00007f2ced0f8580(0000) GS:ffff93825a800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2ced0c3280 CR3: 0000000107069005 CR4: 00000000001706e0 Call Trace: event_hist_trigger+0x463/0x5f0 ? find_held_lock+0x32/0x90 ? sched_clock_cpu+0xe/0xd0 ? lock_release+0x155/0x440 ? kernel_init_free_pages+0x6d/0x90 ? preempt_count_sub+0x9b/0xd0 ? kernel_init_free_pages+0x6d/0x90 ? get_page_from_freelist+0x12c4/0x1680 ? __rb_reserve_next+0xe5/0x460 ? ring_buffer_lock_reserve+0x12a/0x3f0 event_triggers_call+0x52/0xe0 ftrace_syscall_enter+0x264/0x2c0 syscall_trace_enter.constprop.0+0x1ee/0x210 do_syscall_64+0x1c/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Where it triggered a fault on strlen(key) where key was the filename. The reason is that filename is a char * to user space, and the histogram code just blindly dereferenced it, with obvious bad results. I originally tried to use strncpy_from_user/kernel_nofault() but found that there's other places that its dereferenced and not worth the effort. Just do not allow "char *" to act like strings. Link: https://lkml.kernel.org/r/20210715000206.025df9d2@rorschach.local.home Cc: Ingo Molnar Cc: Andrew Morton Cc: Masami Hiramatsu Cc: Tzvetomir Stoyanov Cc: stable@vger.kernel.org Acked-by: Namhyung Kim Acked-by: Tom Zanussi Fixes: 79e577cbce4c4 ("tracing: Support string type key properly") Fixes: 5967bd5c4239 ("tracing: Let filter_assign_type() detect FILTER_PTR_STRING") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: Resize tgid_map to pid_max, not PID_MAX_DEFAULT

2021-07-19T08:01:24Z

commit 4030a6e6a6a4a42ff8c18414c9e0c93e24cc70b8 upstream. Currently tgid_map is sized at PID_MAX_DEFAULT entries, which means that on systems where pid_max is configured higher than PID_MAX_DEFAULT the ftrace record-tgid option doesn't work so well. Any tasks with PIDs higher than PID_MAX_DEFAULT are simply not recorded in tgid_map, and don't show up in the saved_tgids file. In particular since systemd v243 & above configure pid_max to its highest possible 1<<22 value by default on 64 bit systems this renders the record-tgids option of little use. Increase the size of tgid_map to the configured pid_max instead, allowing it to cover the full range of PIDs up to the maximum value of PID_MAX_LIMIT if the system is configured that way. On 64 bit systems with pid_max == PID_MAX_LIMIT this will increase the size of tgid_map from 256KiB to 16MiB. Whilst this 64x increase in memory overhead sounds significant 64 bit systems are presumably best placed to accommodate it, and since tgid_map is only allocated when the record-tgid option is actually used presumably the user would rather it spends sufficient memory to actually record the tgids they expect. The size of tgid_map could also increase for CONFIG_BASE_SMALL=y configurations, but these seem unlikely to be systems upon which people are both configuring a large pid_max and running ftrace with record-tgid anyway. Of note is that we only allocate tgid_map once, the first time that the record-tgid option is enabled. Therefore its size is only set once, to the value of pid_max at the time the record-tgid option is first enabled. If a user increases pid_max after that point, the saved_tgids file will not contain entries for any tasks with pids beyond the earlier value of pid_max. Link: https://lkml.kernel.org/r/20210701172407.889626-2-paulburton@google.com Fixes: d914ba37d714 ("tracing: Add support for recording tgid of tasks") Cc: Ingo Molnar Cc: Joel Fernandes Cc: Signed-off-by: Paul Burton [ Fixed comment coding style ] Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman