[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Regression with commit "x86/pv: Drop int80_bounce from struct pv_vcpu" f75b1a5247b3b311d3aa50de4c0e5f2d68085cb1
On 10/03/2018 16:14, Sander Eikelenboom wrote: > Hi Andrew, > > It seems commit "x86/pv: Drop int80_bounce from struct pv_vcpu" > (f75b1a5247b3b311d3aa50de4c0e5f2d68085cb1) causes an issue on my machine, > an AMD phenom X6. > > When trying to installing a new kernel package which runs the Debian > update-initramfs tools with xen-unstable which happened to be at commit > c9bd8a73656d7435b1055ee8825823aee995993e as last commit the tool stalls > and i get this kernel splat: > > [ 284.910674] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000000 > [ 284.919696] IP: (null) > [ 284.928315] PGD 0 P4D 0 > [ 284.943343] Oops: 0010 [#1] SMP NOPTI > [ 284.957008] Modules linked in: > [ 284.965521] CPU: 5 PID: 24729 Comm: ld-linux.so.2 Not tainted > 4.16.0-rc4-20180305-linus-pvhpatches-doflr+ #1 > [ 284.974154] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS > V1.8B1 09/13/2010 > [ 284.983198] RIP: e030: (null) > [ 284.992006] RSP: e02b:ffffc90001497ed8 EFLAGS: 00010286 > [ 285.000612] RAX: 0000000000000000 RBX: ffff880074c64500 RCX: > ffffffff82f8d1c0 > [ 285.009122] RDX: ffffffff82f8d1c0 RSI: 0000000020020002 RDI: > ffffffff82f8d1c0 > [ 285.017598] RBP: ffff880074c64b7c R08: 0000000000000000 R09: > 0000000000000000 > [ 285.025999] R10: 0000000000000000 R11: 0000000000000000 R12: > ffffffff82f8d1c0 > [ 285.034400] R13: 0000000000000000 R14: 0000000000000000 R15: > ffff880074c64b50 > [ 285.042718] FS: 00007f919fe2eb40(0000) GS:ffff88007d140000(0000) > knlGS:0000000000000000 > [ 285.051001] CS: e033 DS: 002b ES: 002b CR0: 0000000080050033 > [ 285.059458] CR2: 0000000000000000 CR3: 0000000002824000 CR4: > 0000000000000660 > [ 285.067813] Call Trace: > [ 285.075947] ? task_work_run+0x85/0xa0 > [ 285.084025] ? exit_to_usermode_loop+0x72/0x80 > [ 285.091980] ? do_int80_syscall_32+0xfe/0x120 > [ 285.099896] ? entry_INT80_compat+0x7f/0x90 > [ 285.107688] ? fpu__drop+0x23/0x40 > [ 285.115362] Code: Bad RIP value. > [ 285.123072] RIP: (null) RSP: ffffc90001497ed8 > [ 285.130714] CR2: 0000000000000000 > [ 285.138219] ---[ end trace 4d3317497f4ba022 ]--- > [ 285.145671] Fixing recursive fault but reboot is needed! > > After updating xen-unstable to the latest available commit > 185413355fe331cbc926d48568838227234c9a20, > the tool doesn't stall anymore but i still get a kernel splat: > > [ 198.594638] ------------[ cut here ]------------ > [ 198.594641] Invalid address limit on user-mode return > [ 198.594651] WARNING: CPU: 1 PID: 75 at ./include/linux/syscalls.h:236 > do_int80_syscall_32+0xe5/0x120 > [ 198.594652] Modules linked in: > [ 198.594655] CPU: 1 PID: 75 Comm: kworker/1:1 Not tainted > 4.16.0-rc4-20180305-linus-pvhpatches-doflr+ #1 > [ 198.594656] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS > V1.8B1 09/13/2010 > [ 198.594658] Workqueue: events free_work > [ 198.594660] RIP: e030:do_int80_syscall_32+0xe5/0x120 > [ 198.594661] RSP: e02b:ffffc90000b8ff40 EFLAGS: 00010086 > [ 198.594662] RAX: 0000000000000029 RBX: ffffc90000b8ff58 RCX: > ffffffff82868e38 > [ 198.594663] RDX: 0000000000000001 RSI: 0000000000000001 RDI: > 0000000000000001 > [ 198.594664] RBP: ffff880078623980 R08: 0000000000000dfa R09: > 000000000000063b > [ 198.594664] R10: 0000000000000000 R11: 000000000000063b R12: > 0000000000000000 > [ 198.594665] R13: 0000000000000000 R14: 0000000000000000 R15: > 0000000000000000 > [ 198.594672] FS: 00007fa252372b40(0000) GS:ffff88007d040000(0000) > knlGS:0000000000000000 > [ 198.594673] CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 198.594674] CR2: 00000000f7f303e4 CR3: 0000000002824000 CR4: > 0000000000000660 > [ 198.594676] Call Trace: > [ 198.594683] entry_INT80_compat+0x7f/0x90 > [ 198.594685] ? vunmap_page_range+0x2a0/0x340 > [ 198.594686] Code: 03 7f 48 8b 75 00 f7 c6 0e 38 00 00 75 2e 83 65 08 f9 5b > 5d c3 e8 0c fb ff ff e9 53 ff ff ff 48 c7 c7 58 35 57 82 e8 ab 3e 0c 00 <0f> > 0b bf 09 00 00 00 48 89 ee e8 8c 00 0d 00 eb b8 48 89 df e8 > [ 198.594706] ---[ end trace 90bcd2147bc825ef ]--- > > After reverting commit f75b1a5247b3b311d3aa50de4c0e5f2d68085cb1 the issue is > gone. :( This will be the issue which OSSTest is probably bisecting to as well. It is quite odd to see a 64bit process using int80 as opposed to syscall. I'll see about double checking my assembly code, and will also try to identify why my unit tests haven't noticed an issue. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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