Bug 15510
| Summary: | suspicious rcu_dereference_check() usage in scheduler_tick | ||
|---|---|---|---|
| Product: | Process Management | Reporter: | Christian Casteyde (casteyde.christian) |
| Component: | Scheduler | Assignee: | Ingo Molnar (mingo) |
| Status: | RESOLVED UNREPRODUCIBLE | ||
| Severity: | normal | ||
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | Subsystem: | ||
| Regression: | Yes | Bisected commit-id: | |
Still present in -rc3, but with a somewhat different call stack:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
net/netfilter/nf_log.c:55 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by swapper/1:
#0: (nf_log_mutex){+.+...}, at: [<ffffffff814794f7>] nf_log_register+0x57/0x130
stack backtrace:
Pid: 1, comm: swapper Not tainted 2.6.34-rc3 #3
Call Trace:
[<ffffffff8105e058>] lockdep_rcu_dereference+0xb8/0xc0
[<ffffffff81ac8349>] ? log_tg_init+0x0/0x29
[<ffffffff814795b0>] nf_log_register+0x110/0x130
[<ffffffff81ac8349>] ? log_tg_init+0x0/0x29
[<ffffffff81ac836e>] log_tg_init+0x25/0x29
[<ffffffff810001c7>] do_one_initcall+0x37/0x190
[<ffffffff81a9e5bd>] kernel_init+0xe0/0x16c
[<ffffffff815a3152>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff81003074>] kernel_thread_helper+0x4/0x10
[<ffffffff815a40fe>] ? restore_args+0x0/0x30
[<ffffffff81a9e4dd>] ? kernel_init+0x0/0x16c
[<ffffffff81003070>] ? kernel_thread_helper+0x0/0x10
Maybe it's not the same bug, I dont' know...
Update: Still present in -rc4, with the same call stack as in comment #1: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- net/netfilter/nf_log.c:55 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by swapper/1: #0: (nf_log_mutex){+.+...}, at: [<ffffffff814799e7>] nf_log_register+0x57/0x130 stack backtrace: Pid: 1, comm: swapper Not tainted 2.6.34-rc4 #1 Call Trace: [<ffffffff8105e2e8>] lockdep_rcu_dereference+0xb8/0xc0 [<ffffffff81ac83b9>] ? log_tg_init+0x0/0x29 [<ffffffff81479aa0>] nf_log_register+0x110/0x130 [<ffffffff81ac83b9>] ? log_tg_init+0x0/0x29 [<ffffffff81ac83de>] log_tg_init+0x25/0x29 [<ffffffff810001c7>] do_one_initcall+0x37/0x190 [<ffffffff81a9e5bd>] kernel_init+0xe0/0x16c [<ffffffff815a36e2>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff81003074>] kernel_thread_helper+0x4/0x10 [<ffffffff815a467e>] ? restore_args+0x0/0x30 It may be another bug, so maybe I should report it separatly. I'm quite convinced it's not the same bug, I didn't managed to get the initial call stack anymore, but the new warning is always triggered. I'm opening another bug to trace it, and I'm closing this one. |
Acer Aspire 1511LMi Athlon 64 3000 in 64bits mode 1.2 GB RAM Bluewhite 64 13 (64 bits port of Slackware) Since 2.6.34-rc1, I get the following warning at boot on my computer, when I use debugging/kernel hacking options. This warning didn't occur with previous kernels, however it may be because some new checks were added in 34-rc1. hard-irq read-recursion/132: ok | soft-irq read-recursion/132: ok | hard-irq read-recursion/213: ok | soft-irq read-recursion/213: ok | hard-irq read-recursion/231: ok | soft-irq read-recursion/231: ok | hard-irq read-recursion/312: ok | soft-irq read-recursion/312: ok | hard-irq read-recursion/321: ok | soft-irq read-recursion/321: ok | ------------------------------------------------------- Good, all 218 testcases passed! | --------------------------------- ODEBUG: 10 of 10 active objects replaced =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- kernel/sched_fair.c:3479 invoked rcu_dereference_check() without protection! other info that might help us debug this: no locks held by swapper/0. stack backtrace: Pid: 0, comm: swapper Not tainted 2.6.34-rc1 #2 Call Trace: <IRQ> [<ffffffff8106b081>] lockdep_rcu_dereference+0x91/0xa0 [<ffffffff8103db8c>] scheduler_tick+0x1ec/0x2d0 [<ffffffff8104d93f>] update_process_times+0x4f/0x70 [<ffffffff81067277>] tick_periodic+0x27/0x70 [<ffffffff810672df>] tick_handle_periodic+0x1f/0x70 [<ffffffff81005f29>] timer_interrupt+0x19/0x20 [<ffffffff8107edda>] handle_IRQ_event+0x3a/0xd0 [<ffffffff81081628>] handle_level_irq+0x98/0x130 [<ffffffff810056c6>] handle_irq+0x46/0xa0 [<ffffffff8100496e>] do_IRQ+0x6e/0xf0 [<ffffffff8157f213>] ret_from_intr+0x0/0xf <EOI> [<ffffffff8157ee48>] ? _raw_spin_unlock_irqrestore+0x68/0x80 [<ffffffff8107f880>] __setup_irq+0x190/0x360 [<ffffffff8107fa7a>] setup_irq+0x2a/0x40 [<ffffffff81aaee42>] setup_default_timer_irq+0x12/0x20 [<ffffffff81aaee67>] hpet_time_init+0x17/0x20 [<ffffffff81aaee1a>] x86_late_time_init+0xa/0x20 [<ffffffff81aade53>] start_kernel+0x2c3/0x380 [<ffffffff81aad28b>] x86_64_start_reservations+0x9b/0xb0 [<ffffffff81aad391>] x86_64_start_kernel+0xf1/0x120 Fast TSC calibration using PIT Detected 2144.644 MHz processor. Calibrating delay loop (skipped), value calculated using timer frequency.. 4291.00 BogoMIPS (lpj=7148813) Mount-cache hash table entries: 256 tseg: 0000000000 CPU: Physical Processor ID: 0 CPU: Processor Core ID: 0 mce: CPU supports 5 MCE banks Performance Events: AMD PMU driver. ... This machine is uniprocessor, the kernel is not built with SMP support.