February 2013 - kernelnewbies@kernelnewbies.org

How to analyze kernel Oops dump
by Manavendra Nath Manav Feb. 6, 2013

Feb. 6, 2013

I am running Linux 3.4.0 on embedded ARM target and getting following Oops every-time. I am not able to pin-point the reason for crash and which driver module triggered it. How can I decode the values in the registers at the time of crash. It's showing all in hex. [ 492.713897] ------------[ cut here ]------------ [ 492.718841] WARNING: at mm/slub.c:3415 ksize+0x70/0xc4() [ 492.725311] ---[ end trace 90a5ae2bdb3ab657 ]--- [ 492.915618] ------------[ cut here ]------------ [ 492.920593] WARNING: at mm/slub.c:3415 ksize+0x70/0xc4() [ 492.927032] ---[ end trace 90a5ae2bdb3ab658 ]--- [ 493.113464] Unable to handle kernel paging request at virtual address f6b9f777 [ 493.124298] pgd = ec4c4000 [ 493.127166] [f6b9f777] *pgd=00000000 [ 493.130981] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 493.136596] Modules linked in: snd_soc_omap5_nbtevo snd_soc_nbtevo_j5 snd_soc_omap_mcbsp snd_soc_omap snd_soc_core regmap_spi snd_pcm snd_timer snd soundcore snd_page_alloc smsc95xx stm_arm stm_fw stmmac asix usbnet dev_navsens hbiipc ehci_hcd usbcore spi_omap2_mcspi_slave usb_common [ 493.163421] CPU: 0 Tainted: G W (3.4.0 #15) [ 493.169158] PC is at __kmalloc_track_caller+0xa4/0x1ec [ 493.174591] LR is at 0x80569dc0 [ 493.177917] pc : [<801094d8>] lr : [<80569dc0>] psr: a0000113 [ 493.177947] sp : 80569dc0 ip : 89011b70 fp : 80569dfc [ 493.190124] r10: 00001fea r9 : 00000001 r8 : 00000000 [ 493.195648] r7 : 00000940 r6 : 000000d1 r5 : ed002900 r4 : f6b9f777 [ 493.202575] r3 : 80568000 r2 : 00000000 r1 : 08aa8000 r0 : 80589c00 [ 493.209503] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel [ 493.217254] Control: 10c5387d Table: ec4c406a DAC: 00000015 [ 493.223358] [ 493.223358] PC: 0x80109458: [ 493.227874] 9458 e50b2030 9a000006 e2405001 e1a03625 e16f2f13 e2622020 ebfff28d e1a05000 [ 493.236633] 9478 ea000063 ebffef61 e3500010 e1a05000 9a00005f e1a0e00d e3cead7f e3ca303f [ 493.245361] 9498 e59f0178 e5954000 e5938014 e7901108 e084c001 e59ca004 e7944001 e3540000 [ 493.254089] 94b8 1a000005 e1a00005 e1a01006 e51b2030 eb0b01e9 e1a04000 ea00001d e5952014 [ 493.262817] 94d8 e7941002 e10f8000 f10c0080 e5939014 e595e000 e790c109 e1a0200e e792900c [ 493.271545] 94f8 e1590004 1a00000c e28ee004 e79ee00c e15e000a 1a000008 e782100c e5932014 [ 493.280273] 9518 e28e3002 e595c000 e7900102 e28cc004 e78c3000 e3a03001 ea000000 e3a03000 [ 493.289001] 9538 e121f008 e3530000 0affffd1 e1a00005 ebffeb01 e7e017d6 e3540000 03a01000 [ 493.297729] [ 493.297729] LR: 0x80569d40: [ 493.302246] 9d40 00000000 803616d0 0000560c ec430480 80569d74 80569d60 801094d8 a0000113 [ 493.310974] 9d60 ffffffff 80569dac 80569dfc 80569d78 8000e598 80008494 80589c00 08aa8000 [ 493.319702] 9d80 00000000 80568000 f6b9f777 ed002900 000000d1 00000940 00000000 00000001 [ 493.328460] 9da0 00001fea 80569dfc 89011b70 80569dc0 80569dc0 801094d8 a0000113 ffffffff [ 493.337188] 9dc0 80107b00 80104160 80569e04 80336530 8033ef68 ec5c2840 ed002100 000000d1 [ 493.345916] 9de0 80336530 00000881 00000001 00000000 80569e24 80569e00 80335ec0 80109440 [ 493.354644] 9e00 ed0b8000 0000002b 838512c0 87c20100 00000800 ed0b8600 80569e3c 80569e28 [ 493.363372] 9e20 80336530 80335e6c 00000000 ed0b84c0 80569e84 80569e40 7f078788 80336510 [ 493.372100] [ 493.372100] SP: 0x80569d40: [ 493.376617] 9d40 00000000 803616d0 0000560c ec430480 80569d74 80569d60 801094d8 a0000113 [ 493.385345] 9d60 ffffffff 80569dac 80569dfc 80569d78 8000e598 80008494 80589c00 08aa8000 [ 493.394073] 9d80 00000000 80568000 f6b9f777 ed002900 000000d1 00000940 00000000 00000001 [ 493.402832] 9da0 00001fea 80569dfc 89011b70 80569dc0 80569dc0 801094d8 a0000113 ffffffff [ 493.411560] 9dc0 80107b00 80104160 80569e04 80336530 8033ef68 ec5c2840 ed002100 000000d1 [ 493.420288] 9de0 80336530 00000881 00000001 00000000 80569e24 80569e00 80335ec0 80109440 [ 493.429016] 9e00 ed0b8000 0000002b 838512c0 87c20100 00000800 ed0b8600 80569e3c 80569e28 [ 493.437744] 9e20 80336530 80335e6c 00000000 ed0b84c0 80569e84 80569e40 7f078788 80336510 [ 493.446472] [ 493.446472] IP: 0x89011af0: [ 493.450988] 1af0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.459716] 1b10 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.468444] 1b30 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.477172] 1b50 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.485900] 1b70 f6b9f777 00001fea 880fa100 880f8a00 00000000 00000000 00000000 00000000 [ 493.494659] 1b90 00000000 00000000 00000000 00000000 ec438be0 00001710 88d88700 88d91520 [ 493.503387] 1bb0 00000000 00000000 00000000 00000000 805b571c 00000001 00000000 00000000 [ 493.512115] 1bd0 00000001 00000000 00000000 89011bdc 89011bdc 00000000 89011be8 89011be8 [ 493.520843] [ 493.520843] FP: 0x80569d7c: [ 493.525360] 9d7c 08aa8000 00000000 80568000 f6b9f777 ed002900 000000d1 00000940 00000000 [ 493.534088] 9d9c 00000001 00001fea 80569dfc 89011b70 80569dc0 80569dc0 801094d8 a0000113 [ 493.542816] 9dbc ffffffff 80107b00 80104160 80569e04 80336530 8033ef68 ec5c2840 ed002100 [ 493.551544] 9ddc 000000d1 80336530 00000881 00000001 00000000 80569e24 80569e00 80335ec0 [ 493.560272] 9dfc 80109440 ed0b8000 0000002b 838512c0 87c20100 00000800 ed0b8600 80569e3c [ 493.569000] 9e1c 80569e28 80336530 80335e6c 00000000 ed0b84c0 80569e84 80569e40 7f078788 [ 493.577758] 9e3c 80336510 80569e64 80569e50 00000040 00000040 0000002c 83851000 80569e84 [ 493.586486] 9e5c ed0b8600 8900f900 8033f1b4 7f0781f8 0000012c 8900f908 00000040 80569ebc [ 493.595214] [ 493.595214] R0: 0x80589b80: [ 493.599731] 9b80 00000000 00000000 00000000 00000000 80589b90 80589b90 00000000 00000000 [ 493.608459] 9ba0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.617187] 9bc0 00000080 8901d080 00000008 8901d0c0 00008000 0000000f 8901d100 00000002 [ 493.625915] 9be0 8900d000 0000002c 8901d000 8901d040 00000001 00001000 00000000 00000001 [ 493.634643] 9c00 08aa8000 08ab0000 000107ff 00000001 000ed593 000ffffe 00000000 00000032 [ 493.643371] 9c20 0000fffa 00000001 ed002100 00000003 ed18a9d0 ed1b6c00 00000012 89021200 [ 493.652099] 9c40 0003ffff ed003580 ed002480 00000064 00000011 0001ffff 89121200 ed003600 [ 493.660827] 9c60 00100000 ed00c000 00000003 ed002100 00000001 804bf780 00000000 00000004 [ 493.669555] [ 493.669586] R3: 0x80567f80: [ 493.674102] 7f80 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.682830] 7fa0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.691558] 7fc0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.700286] 7fe0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.709014] 8000 00000000 00000104 00000000 8058bad8 805afcc0 00000000 00000015 8900f380 [ 493.717742] 8020 8058bad8 ec8c8000 00000000 ec81efc0 803ce744 00000000 80569f6c 80569ee8 [ 493.726470] 8040 803ce4a8 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.735198] 8060 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 493.743927] [ 493.743927] R4: 0xf6b9f6f7: [ 493.748474] f6f4 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.757202] f714 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.765960] f734 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.774688] f754 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.783416] f774 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.792175] f794 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.800903] f7b4 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.809631] f7d4 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.818389] f7f4 ******** ******** ******** ******** ******** ******** ******** ******** [ 493.827117] [ 493.827117] R5: 0xed002880: [ 493.831665] 2880 80569b58 00004000 00000005 00000800 00000800 00000000 00000006 00030010 [ 493.840393] 28a0 00030010 00000002 00004001 00000001 00000000 00000800 00000040 00000000 [ 493.849121] 28c0 ed0003c0 ed002844 ed002944 ed362c40 ed002850 ed002950 ec9f8950 ec9f8940 [ 493.857849] 28e0 805b7168 ed362cc0 00000001 00000007 ed001440 fdfcbc7b ff53ffaf 7be877af [ 493.866577] 2900 80569b70 00004000 00000006 00001000 00001000 00000000 00000002 00030008 [ 493.875305] 2920 00030008 00000001 00004001 00000001 00000000 00001000 00000040 00000000 [ 493.884033] 2940 ed000400 ed0028c4 ed0029c4 ed362300 ed0028d0 ed0029d0 ec9f8950 ec9f8940 [ 493.892761] 2960 805b7168 ed362380 00000001 00000007 ed001480 fb9d6fe0 fb7eb763 b9fe336a [ 493.901489] Process swapper/0 (pid: 0, stack limit = 0x805682f8) [ 493.907867] Stack: (0x80569dc0 to 0x8056a000) [ 493.912475] 9dc0: 80107b00 80104160 80569e04 80336530 8033ef68 ec5c2840 ed002100 000000d1 [ 493.921173] 9de0: 80336530 00000881 00000001 00000000 80569e24 80569e00 80335ec0 80109440 [ 493.929840] 9e00: ed0b8000 0000002b 838512c0 87c20100 00000800 ed0b8600 80569e3c 80569e28 [ 493.938507] 9e20: 80336530 80335e6c 00000000 ed0b84c0 80569e84 80569e40 7f078788 80336510 [ 493.947204] 9e40: 80569e64 80569e50 00000040 00000040 0000002c 83851000 80569e84 ed0b8600 [ 493.955871] 9e60: 8900f900 8033f1b4 7f0781f8 0000012c 8900f908 00000040 80569ebc 80569e88 [ 493.964569] 9e80: 8033f23c 7f078204 8900d9c8 0000608f cf3ece3f 00000001 8056a08c 8033f1b4 [ 493.973236] 9ea0: 00000102 0000000a 00000000 00000003 80569ef4 80569ec0 80045fb4 8033f1c0 [ 493.981903] 9ec0: 00000000 800a1a74 8056fbc0 80568000 00000000 ffffffff 80569f74 8000406a [ 493.990600] 9ee0: 410fc0f0 00000000 80569f0c 80569ef8 8004659c 80045e94 0000020c 00000078 [ 493.999267] 9f00: 80569f24 80569f10 8000fa08 80046550 fa212000 80569f40 80569f3c 80569f28 [ 494.007934] 9f20: 80008658 8000f988 8000fd50 60000013 80569f94 80569f40 8000e600 8000861c [ 494.016632] 9f40: 80568018 8000fd1c 00000000 805d75c0 00000002 805d6d00 8900aa80 8058cbcc [ 494.025299] 9f60: 8000406a 410fc0f0 00000000 80569f94 80569f74 80569f88 8002633c 8000fd50 [ 494.033966] 9f80: 60000013 ffffffff 80569fa4 80569f98 80010130 8000fd28 80569fbc 80569fa8 [ 494.042663] 9fa0: 803b9c0c 80010080 8054ff08 80589a10 80569ff4 80569fc0 8051f828 803b9b9c [ 494.051330] 9fc0: 00000000 00000000 8051f278 00000000 00000000 80548098 00000000 10c5387d [ 494.059997] 9fe0: 80588dbc 80547c94 00000000 80569ff8 80008044 8051f580 00000000 00000000 [ 494.068664] Backtrace: [ 494.071289] [<80109434>] (__kmalloc_track_caller+0x0/0x1ec) from [<80335ec0>] (__alloc_skb+0x60/0xfc) [ 494.081085] [<80335e60>] (__alloc_skb+0x0/0xfc) from [<80336530>] (__netdev_alloc_skb+0x2c/0x54) [ 494.090423] [<80336504>] (__netdev_alloc_skb+0x0/0x54) from [<7f078788>] (stmmac_poll+0x590/0x794 [stmmac]) [ 494.100738] r4:ed0b84c0 r3:00000000 [ 494.104553] [<7f0781f8>] (stmmac_poll+0x0/0x794 [stmmac]) from [<8033f23c>] (net_rx_action+0x88/0x1f0) [ 494.114440] [<8033f1b4>] (net_rx_action+0x0/0x1f0) from [<80045fb4>] (__do_softirq+0x12c/0x260) [ 494.123657] [<80045e88>] (__do_softirq+0x0/0x260) from [<8004659c>] (irq_exit+0x58/0xb0) [ 494.132263] [<80046544>] (irq_exit+0x0/0xb0) from [<8000fa08>] (handle_IRQ+0x8c/0xc8) [ 494.140563] r4:00000078 r3:0000020c [ 494.144378] [<8000f97c>] (handle_IRQ+0x0/0xc8) from [<80008658>] (gic_handle_irq+0x48/0x6c) [ 494.153228] r5:80569f40 r4:fa212000 [ 494.157043] [<80008610>] (gic_handle_irq+0x0/0x6c) from [<8000e600>] (__irq_svc+0x40/0x70) [ 494.165802] Exception stack(0x80569f40 to 0x80569f88) [ 494.171173] 9f40: 80568018 8000fd1c 00000000 805d75c0 00000002 805d6d00 8900aa80 8058cbcc [ 494.179840] 9f60: 8000406a 410fc0f0 00000000 80569f94 80569f74 80569f88 8002633c 8000fd50 [ 494.188507] 9f80: 60000013 ffffffff [ 494.192230] r5:60000013 r4:8000fd50 [ 494.196014] [<8000fd1c>] (default_idle+0x0/0x3c) from [<80010130>] (cpu_idle+0xbc/0x120) [ 494.204620] [<80010074>] (cpu_idle+0x0/0x120) from [<803b9c0c>] (rest_init+0x7c/0x94) [ 494.212921] [<803b9b90>] (rest_init+0x0/0x94) from [<8051f828>] (start_kernel+0x2b4/0x2fc) [ 494.221710] r4:80589a10 r3:8054ff08 [ 494.225494] [<8051f574>] (start_kernel+0x0/0x2fc) from [<80008044>] (0x80008044) [ 494.233367] Code: eb0b01e9 e1a04000 ea00001d e5952014 (e7941002) [ 494.240142] ---[ end trace 90a5ae2bdb3ab659 ]--- [ 494.245117] Kernel panic - not syncing: Fatal exception in interrupt [ 494.251892] CPU1: stopping [ 494.254760] Backtrace: [ 494.257354] [<80012f64>] (dump_backtrace+0x0/0x114) from [<803c76fc>] (dump_stack+0x20/0x24) [ 494.266204] r6:00000001 r5:00000001 r4:ed091f70 r3:00000000 [ 494.266235] [<803c76dc>] (dump_stack+0x0/0x24) from [<80014944>] (handle_IPI+0x10c/0x1e4) [ 494.273132] [<80014838>] (handle_IPI+0x0/0x1e4) from [<80008674>] (gic_handle_irq+0x64/0x6c) [ 494.289703] r7:ed091ed4 r6:ffffffff r5:ed091ea0 r4:fa212000 [ 494.289703] [<80008610>] (gic_handle_irq+0x0/0x6c) from [<8000e600>] (__irq_svc+0x40/0x70) [ 494.304382] Exception stack(0xed091ea0 to 0xed091ee8) [ 494.304382] 1ea0: ed090028 ed091ee8 ed090000 805f8b00 00000202 ed090028 ffffffff ed091f70 [ 494.312194] 1ec0: 0000000a 00000001 00000000 ed091f1c 00000000 ed091ee8 00000001 80045eec [ 494.326873] 1ee0: 20000113 ffffffff [ 494.327819] r5:20000113 r4:80045eec [ 494.334320] [<80045e88>] (__do_softirq+0x0/0x260) from [<8004659c>] (irq_exit+0x58/0xb0) [ 494.342834] [<80046544>] (irq_exit+0x0/0xb0) from [<80014908>] (handle_IPI+0xd0/0x1e4) [ 494.351165] r4:00000000 r3:00000001 [ 494.354949] [<80014838>] (handle_IPI+0x0/0x1e4) from [<80008674>] (gic_handle_irq+0x64/0x6c) [ 494.363830] r7:ed091fa4 r6:ffffffff r5:ed091f70 r4:fa212000 [ 494.369812] [<80008610>] (gic_handle_irq+0x0/0x6c) from [<8000e600>] (__irq_svc+0x40/0x70) [ 494.378509] Exception stack(0xed091f70 to 0xed091fb8) [ 494.378509] 1f60: ed090008 8000fd1c 00000000 805d75c0 [ 494.392425] 1f80: 00000001 00000001 805d6ff0 805d7004 8000406a 410fc0f0 00000000 ed091fc4 [ 494.398132] 1fa0: ed091fa4 ed091fb8 8002633c 8000fd50 60000013 ffffffff [ 494.407958] r5:60000013 r4:8000fd50 [ 494.407958] [<8000fd1c>] (default_idle+0x0/0x3c) from [<80010130>] (cpu_idle+0xbc/0x120) [ 494.420257] [<80010074>] (cpu_idle+0x0/0x120) from [<803c4538>] (secondary_start_kernel+0x110/0x128) [ 494.429382] [<803c4428>] (secondary_start_kernel+0x0/0x128) from [<803c3e74>] (__enable_mmu+0x0/0x2c) [ 494.439575] r6:10c0387d r5:00000015 r4:ed08006a r3:803c3e5c [ 494.445556] panic occurred, switching back to text console [ 497.913726] [ 497.913726] [ 497.913726] Error: McSPI_RX_DMA: FIFO Overrun..(1) [ 497.913726] -- Manavendra Nath Manav

3 2

Process exit codes
by Grzegorz Dwornicki Feb. 6, 2013

Feb. 6, 2013

Hi Can I kill process by changing its exit codes in task_struct structure? Lets do this in 2 steps: 1. Modify the exit codes in task_struct 2. Call schedule I want to do something like kill -9 on specyfic process using kernel module Thanks G.

3 5

open image file
by horseriver Feb. 5, 2013

Feb. 5, 2013

hi: Is there mothod to look into a image file ? How can I know its filesystem? I have mounted my fd0 to /mnt with -t tmpfs ,but I find nothing under /mnt.How can I touch the files in image? thanks!

6 8

early_ioremap and early_iounmap
by leo kirotawa Feb. 5, 2013

Feb. 5, 2013

Hi, I'm trying to do some maps in early kernel boot and grab some error when I try unmap a pointer/memory that mapped it before. Basically it shows me the message: size is not consistent. I'm maping it like this: table = early_ioremap(offset_address, table_size); and unmap it : early_iounmap(table, table_size); What to me seems the correct. I also try this way: early_iounmap(table, sizeof(*table)); but the same error is shown. Does anyone have any idea about using ioremap and iounmap? Thanks, Leo. -- "smile and wave" - =D + o/ (Penguins of Madagascar) 日本語の学生です。コンピュータサイエンスの学位.

1 0

/root/.debug/ ... ?
by Shraddha Kamat Feb. 5, 2013

Feb. 5, 2013

Might be a silly question - but since I am a newbie I am trying to understand the reason for existance for most of the stuff that I find while reading the code --- here is my question -- I see that there is a directory - /root/.debug/lib/modules/3.8.0-rc5 +/kernel/net/8021q/8021q.ko/8a73921f509a12a1cd7fb49dd8d1203197294c9e Why is this directory here for ? What is this file 8a73921f509a12a1cd7fb49dd8d1203197294c9e ? -- Shraddha

2 3

Kernel DSO ?
by Shraddha Kamat Feb. 5, 2013

Feb. 5, 2013

What is a kernel DSO ? I encountered it while I was reading perf code. -- shraddha

3 2

Linux Kernel Networking document (free, 178 pages doc)
by Rami Rosen Feb. 4, 2013

Feb. 4, 2013

Hi everyone, You can find here an up to date and detailed document in pdf (178 pages) about Linux Kernel Networking; going deep into design and implementation details as well as the theory behind it: http://media.wix.com/ugd//295986_931b8bcf34d93419d46e05b5aa5d0216.pdf I believe that developers/sysadmins/researchers/students may find help with it. regards, Rami Rosen http://ramirose.wix.com/ramirosen

16 22

newbie's question
by horseriver Feb. 4, 2013

Feb. 4, 2013

hi:) I use fdisk to add a new partion on a image file. I find the start of partion 1 is alwayes set to 63 by default. That means partion 1 start at 63*512=32256 byte. Here is my question: 1. The region from 512th bytes to 32256th bytes will do what ? Why partion 1 don't follow MSR's location ? 2. The image's magic number is at which offset ? Thanks!

3 2

Re: Question about printking
by Ezequiel Garcia Feb. 4, 2013

Feb. 4, 2013

Hi Joe, On Sat, Feb 2, 2013 at 4:43 PM, Joe Perches <joe(a)perches.com> wrote: > On Sat, 2013-02-02 at 16:30 -0300, Ezequiel Garcia wrote: >> ptr = kmalloc(sizeof(foo)); >> if (!ptr) { >> pr_err("Cannot allocate memory for foo\n"); >> return -ENOMEM; >> } >> His argue against it was that kmalloc already takes care of reporting/printking >> a good deal of interesting information when this happens. > >> Can someone expand a bit on this whole idea? (of abuse of printing, >> or futility of printing). > > k.alloc() takes a GFP_ flag as an arg. > > One of those GFP flags is __GFP_NOWARN. > > For all failed allocs without GFP_NOWARN > a message is emitted and a dump_stack is > done. > > (see: mm/page_alloc.c warn_alloc_failed()) > > So, most all of these printks after > k.alloc()'s are not necessary. > > Thanks for the explanation. BTW, I see you've made some patches to fix exactly this. Nice job. Regards, -- Ezequiel

1 0

Question: copy_process() and CLONE_NEWNS
by Kevin Wilson Feb. 4, 2013

Feb. 4, 2013

Hi all, question: In copy_process() we have: static struct task_struct *copy_process(unsigned long clone_flags, unsigned long stack_start, struct pt_regs *regs, unsigned long stack_size, int __user *child_tidptr, struct pid *pid, int trace) { int retval; struct task_struct *p; int cgroup_callbacks_done = 0; if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) return ERR_PTR(-EINVAL); ... ... see :http://lxr.free-electrons.com/source/kernel/fork.c#L1128 Why is the CLONE_NEWNS, when set, cause an error in copy_process(), as shown above ? is it not permitted that CLONE_NEWNS will be set ? rgs, Kevin

4 3