| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAOesGMhB2Akf_B2_J3LVdt1bDvcsTE7+8Kq=NvsXmkf3EwGsiw@mail.gmail.com> Date: Fri, 8 Nov 2013 12:45:34 -0800 From: Olof Johansson <olof@...om.net> To: Stephen Boyd <sboyd@...eaurora.org> Cc: Kevin Hilman <khilman@...aro.org>, Russell King <linux@....linux.org.uk>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, Frederic Weisbecker <fweisbec@...il.com>, Maxime Ripard <maxime.ripard@...e-electrons.com> Subject: Re: [PATCH] ARM: Support arch_irq_work_raise() via self IPIs On Fri, Nov 8, 2013 at 12:06 PM, Olof Johansson <olof@...om.net> wrote: > On Mon, Oct 28, 2013 at 11:00 PM, Stephen Boyd <sboyd@...eaurora.org> wrote: >> On 10/28, Kevin Hilman wrote: >>> Stephen Boyd <sboyd@...eaurora.org> writes: >>> >>> > This will allow the scheduler tick to be restarted if we're in >>> > full NOHZ mode. >>> > >>> > Cc: Kevin Hilman <khilman@...aro.org> >>> > Cc: Frederic Weisbecker <fweisbec@...il.com> >>> > Signed-off-by: Stephen Boyd <sboyd@...eaurora.org> >>> >>> Minor nit, but I'd prefer a more verbose changelog (I forget things >>> quickly and like to rely on changelogs for my memory.) Probably worth >>> adding something like: "By default, irq_work is tied to the tick >>> processing (update_process_times()) but in full NOHZ mode, no tick means >>> no IRQ work. In order for IRQ work to be done in full NOHZ mode, a >>> self-IPI is used to process IRQ work." >>> >>> Other than the changelog nit, patch looks good, feel free to add >>> >>> Reviewed-by: Kevin Hilman <khilman@...aro.org> >>> >>> If Russell is OK with this, it can go to his patch system. >>> >> >> Fair enough. This is what I came up with. I'll send it off to the >> patch tracker in about 12 hours if nobody else has anymore >> comments. >> >> ----8<----- >> ARM: Support arch_irq_work_raise() via self IPIs >> >> By default, IRQ work is run from the tick interrupt (see >> irq_work_run() in update_process_times()). When we're in full >> NOHZ mode, restarting the tick requires the use of IRQ work and >> if the only place we run IRQ work is in the tick interrupt we >> have an unbreakable cycle. Implement arch_irq_work_raise() via >> self IPIs to break this cycle and get the tick started again. >> Note that we implement this via IPIs which are only available on >> SMP builds. This shouldn't be a problem because full NOHZ is only >> supported on SMP builds anyway. >> >> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org> >> Reviewed-by: Kevin Hilman <khilman@...aro.org> >> Cc: Frederic Weisbecker <fweisbec@...il.com> > > > Hm, so I think this just landed in -next, which seems... late for > 3.13. Anyway, it causes boot failures on Cubieboards (Allwinner A10), > I just bisected it down to this patch (fails to boot > multi_v7_defconfig, no console output at all). > > Unfortunately I'm not getting any debug_ll output from the board at > the moment, so I can't actually get to a panic stack or other error > info. :( I hope I can get back to you with one later today. Turns out that I hit this on the BeagleBone as well, and I got a trace out of it. Seems like this might be broken on all non-SMP platforms built with CONFIG_SMP=y? [ 0.206322] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 0.214752] pgd = c0004000 [ 0.217628] [00000000] *pgd=00000000 [ 0.221421] Internal error: Oops: 80000005 [#1] SMP ARM [ 0.226890] Modules linked in: [ 0.230136] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-rc6-00018-g8d45144-dirty #16 [ 0.238646] task: de05b440 ti: de05c000 task.ti: de05c000 [ 0.244294] PC is at 0x0 [ 0.247010] LR is at arch_irq_work_raise+0x3c/0x48 [ 0.252034] pc : [<00000000>] lr : [<c0019590>] psr: 60000193 [ 0.252034] sp : de05dd60 ip : 00000001 fp : 00000000 [ 0.264029] r10: c085e2f0 r9 : de05c000 r8 : c07be0a4 [ 0.269496] r7 : de05c000 r6 : de05c000 r5 : c07c5778 r4 : c0824554 [ 0.276305] r3 : 00000000 r2 : 00000000 r1 : 00000006 r0 : c0529a58 [ 0.283116] Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel [ 0.290818] Control: 10c5387d Table: 80004019 DAC: 00000017 [ 0.296821] Process swapper/0 (pid: 1, stack limit = 0xde05c248) [ 0.303094] Stack: (0xde05dd60 to 0xde05e000) [ 0.307677] dd60: c07b9dbc c00cb2dc 00000001 c08242c0 c08242c0 60000113 c07be0a8 c00b0590 [ 0.316191] dd80: de05c000 c085e2f0 c08242c0 c08242c0 c1414c28 c00b07cc de05b440 c1414c28 [ 0.324705] dda0: c08242c0 c00b0af8 c0862bb0 c0862db0 c1414cd8 de05c028 c0824840 de05ddb8 [ 0.333218] ddc0: 00000000 00000009 00000001 00000024 c07be0a8 c07be0a4 de05c000 c085e2f0 [ 0.341731] dde0: 00000000 c004a4b0 00000010 de00d2dc 00000054 00000100 00000024 00000000 [ 0.350244] de00: de05c028 0000000a ffff8ae7 00200040 00000016 de05c000 60000193 de05c000 [ 0.358756] de20: 00000054 00000000 00000000 00000000 00000000 c004a704 00000000 de05c008 [ 0.367269] de40: c07ba254 c004aa1c c07c5778 c0014b70 fa200000 00000054 de05de80 c0861244 [ 0.375782] de60: 00000000 c0008634 de05b440 c051c778 20000113 ffffffff de05deb4 c051d0a4 [ 0.384295] de80: 00000001 00000001 00000000 de05b440 c082afac de057ac0 de057ac0 de0443c0 [ 0.392807] dea0: 00000000 00000000 00000000 00000000 c082afbc de05dec8 c009f2a0 c051c778 [ 0.401321] dec0: 20000113 ffffffff 00000000 c016edb0 00000000 000002b0 de057ac0 de057ac0 [ 0.409833] dee0: 00000000 c016ee40 c0875e50 de05df2e de057ac0 00000000 00000013 00000000 [ 0.418345] df00: 00000000 c016f054 de043600 de0443c0 c008eb38 de004ec0 c0875e50 c008eb44 [ 0.426858] df20: 00000012 00000000 00000000 3931f0f8 00000000 00000000 00000014 c0822e84 [ 0.435370] df40: 00000000 c008ed2c 00000000 00000000 00000000 c07b7490 c07b7490 c075ab3c [ 0.443882] df60: 00000000 c00701ac 00000002 00000000 c0070160 dffadb73 7bf8edb4 00000000 [ 0.452394] df80: c051092c 00000000 00000000 00000000 00000000 00000000 00000000 c0510934 [ 0.460907] dfa0: de05aa40 00000000 c051092c c0013ce8 00000000 00000000 00000000 00000000 [ 0.469419] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 0.477930] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 07efffe5 4dfac6f5 [ 0.486468] [<c0019590>] (arch_irq_work_raise+0x3c/0x48) from [<c00cb2dc>] (irq_work_queue+0xe4/0xf8) [ 0.496073] [<c00cb2dc>] (irq_work_queue+0xe4/0xf8) from [<c00b0590>] (rcu_accelerate_cbs+0x1d4/0x1d8) [ 0.505756] [<c00b0590>] (rcu_accelerate_cbs+0x1d4/0x1d8) from [<c00b07cc>] (rcu_start_gp+0x34/0x48) [ 0.515259] [<c00b07cc>] (rcu_start_gp+0x34/0x48) from [<c00b0af8>] (rcu_process_callbacks+0x318/0x608) [ 0.525040] [<c00b0af8>] (rcu_process_callbacks+0x318/0x608) from [<c004a4b0>] (__do_softirq+0x114/0x2a0) [ 0.534989] [<c004a4b0>] (__do_softirq+0x114/0x2a0) from [<c004a704>] (do_softirq+0x6c/0x74) [ 0.543776] [<c004a704>] (do_softirq+0x6c/0x74) from [<c004aa1c>] (irq_exit+0xac/0x100) [ 0.552126] [<c004aa1c>] (irq_exit+0xac/0x100) from [<c0014b70>] (handle_IRQ+0x54/0xb4) [ 0.560466] [<c0014b70>] (handle_IRQ+0x54/0xb4) from [<c0008634>] (omap3_intc_handle_irq+0x60/0x74) [ 0.569885] [<c0008634>] (omap3_intc_handle_irq+0x60/0x74) from [<c051d0a4>] (__irq_svc+0x44/0x5c) [ 0.579196] Exception stack(0xde05de80 to 0xde05dec8) [ 0.584491] de80: 00000001 00000001 00000000 de05b440 c082afac de057ac0 de057ac0 de0443c0 [ 0.593004] dea0: 00000000 00000000 00000000 00000000 c082afbc de05dec8 c009f2a0 c051c778 [ 0.601510] dec0: 20000113 ffffffff [ 0.605202] [<c051d0a4>] (__irq_svc+0x44/0x5c) from [<c051c778>] (_raw_spin_unlock_irq+0x28/0x2c) [ 0.614447] [<c051c778>] (_raw_spin_unlock_irq+0x28/0x2c) from [<c016edb0>] (proc_alloc_inum+0x30/0xa8) [ 0.624220] [<c016edb0>] (proc_alloc_inum+0x30/0xa8) from [<c016ee40>] (proc_register+0x18/0x130) [ 0.633454] [<c016ee40>] (proc_register+0x18/0x130) from [<c016f054>] (proc_mkdir_data+0x44/0x6c) [ 0.642702] [<c016f054>] (proc_mkdir_data+0x44/0x6c) from [<c008eb44>] (register_irq_proc+0x6c/0x128) [ 0.652292] [<c008eb44>] (register_irq_proc+0x6c/0x128) from [<c008ed2c>] (init_irq_proc+0x74/0xb0) [ 0.661706] [<c008ed2c>] (init_irq_proc+0x74/0xb0) from [<c075ab3c>] (kernel_init_freeable+0x84/0x1c8) [ 0.671390] [<c075ab3c>] (kernel_init_freeable+0x84/0x1c8) from [<c0510934>] (kernel_init+0x8/0x150) [ 0.680892] [<c0510934>] (kernel_init+0x8/0x150) from [<c0013ce8>] (ret_from_fork+0x14/0x2c) [ 0.689674] Code: bad PC value [ 0.692984] ---[ end trace 1b75b31a2719ed1c ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists