oprofile, x86: Fix nmi-unsafe callgraph support
Current oprofile's x86 callgraph support may trigger page faults throwing the BUG_ON(in_nmi()) message below. This patch fixes this by using the same nmi-safe copy-from-user code as in perf. ------------[ cut here ]------------ kernel BUG at .../arch/x86/kernel/traps.c:436! invalid opcode: 0000 [#1] SMP last sysfs file: /sys/devices/pci0000:00/0000:00:0a.0/0000:07:00.0/0000:08:04.0/net/eth0/broadcast CPU 5 Modules linked in: Pid: 8611, comm: opcontrol Not tainted 2.6.39-00007-gfe47ae7 #1 Advanced Micro Device Anaheim/Anaheim RIP: 0010:[<ffffffff813e8e35>] [<ffffffff813e8e35>] do_nmi+0x22/0x1ee RSP: 0000:ffff88042fd47f28 EFLAGS: 00010002 RAX: ffff88042c0a7fd8 RBX: 0000000000000001 RCX: 00000000c0000101 RDX: 00000000ffff8804 RSI: ffffffffffffffff RDI: ffff88042fd47f58 RBP: ffff88042fd47f48 R08: 0000000000000004 R09: 0000000000001484 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88042fd47f58 R13: 0000000000000000 R14: ffff88042fd47d98 R15: 0000000000000020 FS: 00007fca25e56700(0000) GS:ffff88042fd40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000074 CR3: 000000042d28b000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process opcontrol (pid: 8611, threadinfo ffff88042c0a6000, task ffff88042c532310) Stack: 0000000000000000 0000000000000001 ffff88042c0a7fd8 0000000000000000 ffff88042fd47de8 ffffffff813e897a 0000000000000020 ffff88042fd47d98 0000000000000000 ffff88042c0a7fd8 ffff88042fd47de8 0000000000000074 Call Trace: <NMI> [<ffffffff813e897a>] nmi+0x1a/0x20 [<ffffffff813f08ab>] ? bad_to_user+0x25/0x771 <<EOE>> Code: ff 59 5b 41 5c 41 5d c9 c3 55 65 48 8b 04 25 88 b5 00 00 48 89 e5 41 55 41 54 49 89 fc 53 48 83 ec 08 f6 80 47 e0 ff ff 04 74 04 <0f> 0b eb fe 81 80 44 e0 ff ff 00 00 01 04 65 ff 04 25 c4 0f 01 RIP [<ffffffff813e8e35>] do_nmi+0x22/0x1ee RSP <ffff88042fd47f28> ---[ end trace ed6752185092104b ]--- Kernel panic - not syncing: Fatal exception in interrupt Pid: 8611, comm: opcontrol Tainted: G D 2.6.39-00007-gfe47ae7 #1 Call Trace: <NMI> [<ffffffff813e5e0a>] panic+0x8c/0x188 [<ffffffff813e915c>] oops_end+0x81/0x8e [<ffffffff8100403d>] die+0x55/0x5e [<ffffffff813e8c45>] do_trap+0x11c/0x12b [<ffffffff810023c8>] do_invalid_op+0x91/0x9a [<ffffffff813e8e35>] ? do_nmi+0x22/0x1ee [<ffffffff8131e6fa>] ? oprofile_add_sample+0x83/0x95 [<ffffffff81321670>] ? op_amd_check_ctrs+0x4f/0x2cf [<ffffffff813ee4d5>] invalid_op+0x15/0x20 [<ffffffff813e8e35>] ? do_nmi+0x22/0x1ee [<ffffffff813e8e7a>] ? do_nmi+0x67/0x1ee [<ffffffff813e897a>] nmi+0x1a/0x20 [<ffffffff813f08ab>] ? bad_to_user+0x25/0x771 <<EOE>> Cc: John Lumby <johnlumby@hotmail.com> Cc: Maynard Johnson <maynardj@us.ibm.com> Cc: <stable@kernel.org> # .37+ Signed-off-by: Robert Richter <robert.richter@amd.com>
This commit is contained in:
Robert Richter
Родитель
8fe7e94eb7
Коммит
a0e3e70243
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@ -11,10 +11,12 @@
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/compat.h>
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#include <linux/highmem.h>
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#include <asm/ptrace.h>
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#include <asm/uaccess.h>
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#include <asm/stacktrace.h>
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#include <linux/compat.h>
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static int backtrace_stack(void *data, char *name)
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{
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@ -36,17 +38,53 @@ static struct stacktrace_ops backtrace_ops = {
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.walk_stack = print_context_stack,
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};
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/* from arch/x86/kernel/cpu/perf_event.c: */
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/*
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* best effort, GUP based copy_from_user() that assumes IRQ or NMI context
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*/
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static unsigned long
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copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
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{
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unsigned long offset, addr = (unsigned long)from;
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unsigned long size, len = 0;
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struct page *page;
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void *map;
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int ret;
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do {
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ret = __get_user_pages_fast(addr, 1, 0, &page);
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if (!ret)
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break;
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offset = addr & (PAGE_SIZE - 1);
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size = min(PAGE_SIZE - offset, n - len);
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map = kmap_atomic(page);
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memcpy(to, map+offset, size);
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kunmap_atomic(map);
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put_page(page);
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len += size;
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to += size;
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addr += size;
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} while (len < n);
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return len;
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}
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#ifdef CONFIG_COMPAT
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static struct stack_frame_ia32 *
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dump_user_backtrace_32(struct stack_frame_ia32 *head)
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{
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/* Also check accessibility of one struct frame_head beyond: */
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struct stack_frame_ia32 bufhead[2];
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struct stack_frame_ia32 *fp;
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unsigned long bytes;
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/* Also check accessibility of one struct frame_head beyond */
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if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
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return NULL;
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if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
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bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
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if (bytes != sizeof(bufhead))
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return NULL;
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fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
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@ -87,12 +125,12 @@ x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
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static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
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{
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/* Also check accessibility of one struct frame_head beyond: */
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struct stack_frame bufhead[2];
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unsigned long bytes;
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/* Also check accessibility of one struct stack_frame beyond */
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if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
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return NULL;
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if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
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bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
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if (bytes != sizeof(bufhead))
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return NULL;
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oprofile_add_trace(bufhead[0].return_address);
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