* WARNING in arch_uprobe_analyze_insn @ 2018-05-14 14:24 syzbot 2018-05-15 13:36 ` Oleg Nesterov 2018-05-18 16:27 ` [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() Oleg Nesterov 0 siblings, 2 replies; 6+ messages in thread From: syzbot @ 2018-05-14 14:24 UTC (permalink / raw) To: bp, hpa, linux-kernel, mingo, oleg, ricardo.neri-calderon, syzkaller-bugs, tglx, x86, yhs Hello, syzbot found the following crash on: HEAD commit: 66e1c94db3cd Merge branch 'x86-pti-for-linus' of git://git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11817107800000 kernel config: https://syzkaller.appspot.com/x/.config?x=fcce42b221691ff9 dashboard link: https://syzkaller.appspot.com/bug?extid=30d675e3ca03c1c351e7 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=143d5417800000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11178e97800000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 insn_complete arch/x86/include/asm/insn.h:147 [inline] WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 uprobe_init_insn arch/x86/kernel/uprobes.c:296 [inline] WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 arch_uprobe_analyze_insn+0x13d/0x15f0 arch/x86/kernel/uprobes.c:861 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 4511 Comm: syz-executor347 Not tainted 4.17.0-rc4+ #46 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 panic+0x22f/0x4de kernel/panic.c:184 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 report_bug+0x252/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 RIP: 0010:insn_complete arch/x86/include/asm/insn.h:147 [inline] RIP: 0010:uprobe_init_insn arch/x86/kernel/uprobes.c:296 [inline] RIP: 0010:arch_uprobe_analyze_insn+0x13d/0x15f0 arch/x86/kernel/uprobes.c:861 RSP: 0018:ffff8801cf277510 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801cf277560 RCX: ffffffff876ccf2a RDX: 0000000000000004 RSI: ffffffff876ce6ab RDI: ffff8801cf27759c RBP: ffff8801cf277628 R08: ffff8801d8c0a5c0 R09: ffff8801cf277560 R10: ffff8801d7ad81d0 R11: ffff8801cf2775af R12: 0000000000000000 R13: dffffc0000000000 R14: ffff8801d7ad8080 R15: ffff8801cf277600 prepare_uprobe kernel/events/uprobes.c:610 [inline] install_breakpoint.isra.21+0x710/0x830 kernel/events/uprobes.c:657 uprobe_mmap+0x6a0/0xcf0 kernel/events/uprobes.c:1089 mmap_region+0x5c8/0x1870 mm/mmap.c:1807 do_mmap+0xde2/0x1360 mm/mmap.c:1535 do_mmap_pgoff include/linux/mm.h:2237 [inline] vm_mmap_pgoff+0x1fb/0x2a0 mm/util.c:357 ksys_mmap_pgoff+0x4c9/0x640 mm/mmap.c:1585 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x43ff29 RSP: 002b:00007ffc922a4898 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ff29 RDX: 0000000000000000 RSI: 0000000000002000 RDI: 000000002000c000 RBP: 00000000006ca018 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000012 R11: 0000000000000212 R12: 0000000000401850 R13: 00000000004018e0 R14: 0000000000000000 R15: 0000000000000000 Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds.. --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: WARNING in arch_uprobe_analyze_insn 2018-05-14 14:24 WARNING in arch_uprobe_analyze_insn syzbot @ 2018-05-15 13:36 ` Oleg Nesterov 2018-05-15 14:48 ` Masami Hiramatsu 2018-05-18 16:27 ` [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() Oleg Nesterov 1 sibling, 1 reply; 6+ messages in thread From: Oleg Nesterov @ 2018-05-15 13:36 UTC (permalink / raw) To: syzbot, Masami Hiramatsu Cc: bp, hpa, linux-kernel, mingo, ricardo.neri-calderon, syzkaller-bugs, tglx, x86, yhs On 05/14, syzbot wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 66e1c94db3cd Merge branch 'x86-pti-for-linus' of git://git.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=11817107800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=fcce42b221691ff9 > dashboard link: https://syzkaller.appspot.com/bug?extid=30d675e3ca03c1c351e7 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=143d5417800000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11178e97800000 doesn't work for me... I guess syscall(__NR_perf_event_open) should trigger perf_uprobe_init() but the hard-coded attr.type doesn't match perf_uprobe->type on my machine... Nevermind, it seems that the code is indeed wrong, uprobe_init_insn() does insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64); /* has the side-effect of processing the entire instruction */ insn_get_length(insn); if (WARN_ON_ONCE(!insn_complete(insn))) return -ENOEXEC; Masami, could your help? What if insn can't be decoded, say, because it is not valid? Can't insn_complete() return F in this case? I think it can... Say, insn_get_immediate() doesn't set immediate.got in err_out path. Unfortunately, insn_get_length() returns void, and I do not see any insn-was-decoded-correctly helper. Perhaps we should simply remove this WARN_ON() ? Alternatively, If am right we can move this check down after the "good_insns" checks, but this doesn't look very clean to me. > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com > > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 insn_complete > arch/x86/include/asm/insn.h:147 [inline] > WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 uprobe_init_insn > arch/x86/kernel/uprobes.c:296 [inline] > WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 > arch_uprobe_analyze_insn+0x13d/0x15f0 arch/x86/kernel/uprobes.c:861 > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 4511 Comm: syz-executor347 Not tainted 4.17.0-rc4+ #46 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1b9/0x294 lib/dump_stack.c:113 > panic+0x22f/0x4de kernel/panic.c:184 > __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 > report_bug+0x252/0x2d0 lib/bug.c:186 > fixup_bug arch/x86/kernel/traps.c:178 [inline] > do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 > RIP: 0010:insn_complete arch/x86/include/asm/insn.h:147 [inline] > RIP: 0010:uprobe_init_insn arch/x86/kernel/uprobes.c:296 [inline] > RIP: 0010:arch_uprobe_analyze_insn+0x13d/0x15f0 > arch/x86/kernel/uprobes.c:861 > RSP: 0018:ffff8801cf277510 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: ffff8801cf277560 RCX: ffffffff876ccf2a > RDX: 0000000000000004 RSI: ffffffff876ce6ab RDI: ffff8801cf27759c > RBP: ffff8801cf277628 R08: ffff8801d8c0a5c0 R09: ffff8801cf277560 > R10: ffff8801d7ad81d0 R11: ffff8801cf2775af R12: 0000000000000000 > R13: dffffc0000000000 R14: ffff8801d7ad8080 R15: ffff8801cf277600 > prepare_uprobe kernel/events/uprobes.c:610 [inline] > install_breakpoint.isra.21+0x710/0x830 kernel/events/uprobes.c:657 > uprobe_mmap+0x6a0/0xcf0 kernel/events/uprobes.c:1089 > mmap_region+0x5c8/0x1870 mm/mmap.c:1807 > do_mmap+0xde2/0x1360 mm/mmap.c:1535 > do_mmap_pgoff include/linux/mm.h:2237 [inline] > vm_mmap_pgoff+0x1fb/0x2a0 mm/util.c:357 > ksys_mmap_pgoff+0x4c9/0x640 mm/mmap.c:1585 > __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] > __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] > __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 > do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x43ff29 > RSP: 002b:00007ffc922a4898 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 > RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ff29 > RDX: 0000000000000000 RSI: 0000000000002000 RDI: 000000002000c000 > RBP: 00000000006ca018 R08: 0000000000000003 R09: 0000000000000000 > R10: 0000000000000012 R11: 0000000000000212 R12: 0000000000401850 > R13: 00000000004018e0 R14: 0000000000000000 R15: 0000000000000000 > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: WARNING in arch_uprobe_analyze_insn 2018-05-15 13:36 ` Oleg Nesterov @ 2018-05-15 14:48 ` Masami Hiramatsu 2018-05-15 16:18 ` Oleg Nesterov 0 siblings, 1 reply; 6+ messages in thread From: Masami Hiramatsu @ 2018-05-15 14:48 UTC (permalink / raw) To: Oleg Nesterov Cc: syzbot, bp, hpa, linux-kernel, mingo, ricardo.neri-calderon, syzkaller-bugs, tglx, x86, yhs On Tue, 15 May 2018 15:36:30 +0200 Oleg Nesterov <oleg@redhat.com> wrote: > On 05/14, syzbot wrote: > > > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 66e1c94db3cd Merge branch 'x86-pti-for-linus' of git://git.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=11817107800000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=fcce42b221691ff9 > > dashboard link: https://syzkaller.appspot.com/bug?extid=30d675e3ca03c1c351e7 > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=143d5417800000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11178e97800000 > > doesn't work for me... > > I guess syscall(__NR_perf_event_open) should trigger perf_uprobe_init() but > the hard-coded attr.type doesn't match perf_uprobe->type on my machine... > > > Nevermind, it seems that the code is indeed wrong, uprobe_init_insn() does > > insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64); > /* has the side-effect of processing the entire instruction */ > insn_get_length(insn); > if (WARN_ON_ONCE(!insn_complete(insn))) > return -ENOEXEC; > > Masami, could your help? > > What if insn can't be decoded, say, because it is not valid? Can't > insn_complete() return F in this case? Yes, as far as it failes to decode. BTW, insn_complete() may not work some errors, it is hard to find all invalid combination of x86 insn. I think the uprobes is fundamentary week about fuzzing code because it can not identify the instruction boundary in user space. > I think it can... Say, insn_get_immediate() doesn't set immediate.got in > err_out path. > > Unfortunately, insn_get_length() returns void, and I do not see any > insn-was-decoded-correctly helper. Perhaps we should simply remove > this WARN_ON() ? Yes, it should just return an error, since user can miss the probe address on user binary and we can not make sure that is on a instruction boundary. > Alternatively, If am right we can move this check down after the "good_insns" > checks, but this doesn't look very clean to me. I think it is enough if arch_uprobe_analyze_insn() returns an error. That makes prepare_uprobe() fail and finally leads uprobe_register() fail. Thank you, > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com > > > > random: sshd: uninitialized urandom read (32 bytes read) > > random: sshd: uninitialized urandom read (32 bytes read) > > random: sshd: uninitialized urandom read (32 bytes read) > > random: sshd: uninitialized urandom read (32 bytes read) > > random: sshd: uninitialized urandom read (32 bytes read) > > WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 insn_complete > > arch/x86/include/asm/insn.h:147 [inline] > > WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 uprobe_init_insn > > arch/x86/kernel/uprobes.c:296 [inline] > > WARNING: CPU: 0 PID: 4511 at arch/x86/kernel/uprobes.c:296 > > arch_uprobe_analyze_insn+0x13d/0x15f0 arch/x86/kernel/uprobes.c:861 > > Kernel panic - not syncing: panic_on_warn set ... > > > > CPU: 0 PID: 4511 Comm: syz-executor347 Not tainted 4.17.0-rc4+ #46 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Call Trace: > > __dump_stack lib/dump_stack.c:77 [inline] > > dump_stack+0x1b9/0x294 lib/dump_stack.c:113 > > panic+0x22f/0x4de kernel/panic.c:184 > > __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 > > report_bug+0x252/0x2d0 lib/bug.c:186 > > fixup_bug arch/x86/kernel/traps.c:178 [inline] > > do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 > > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 > > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 > > RIP: 0010:insn_complete arch/x86/include/asm/insn.h:147 [inline] > > RIP: 0010:uprobe_init_insn arch/x86/kernel/uprobes.c:296 [inline] > > RIP: 0010:arch_uprobe_analyze_insn+0x13d/0x15f0 > > arch/x86/kernel/uprobes.c:861 > > RSP: 0018:ffff8801cf277510 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: ffff8801cf277560 RCX: ffffffff876ccf2a > > RDX: 0000000000000004 RSI: ffffffff876ce6ab RDI: ffff8801cf27759c > > RBP: ffff8801cf277628 R08: ffff8801d8c0a5c0 R09: ffff8801cf277560 > > R10: ffff8801d7ad81d0 R11: ffff8801cf2775af R12: 0000000000000000 > > R13: dffffc0000000000 R14: ffff8801d7ad8080 R15: ffff8801cf277600 > > prepare_uprobe kernel/events/uprobes.c:610 [inline] > > install_breakpoint.isra.21+0x710/0x830 kernel/events/uprobes.c:657 > > uprobe_mmap+0x6a0/0xcf0 kernel/events/uprobes.c:1089 > > mmap_region+0x5c8/0x1870 mm/mmap.c:1807 > > do_mmap+0xde2/0x1360 mm/mmap.c:1535 > > do_mmap_pgoff include/linux/mm.h:2237 [inline] > > vm_mmap_pgoff+0x1fb/0x2a0 mm/util.c:357 > > ksys_mmap_pgoff+0x4c9/0x640 mm/mmap.c:1585 > > __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] > > __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] > > __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 > > do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 > > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > RIP: 0033:0x43ff29 > > RSP: 002b:00007ffc922a4898 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 > > RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ff29 > > RDX: 0000000000000000 RSI: 0000000000002000 RDI: 000000002000c000 > > RBP: 00000000006ca018 R08: 0000000000000003 R09: 0000000000000000 > > R10: 0000000000000012 R11: 0000000000000212 R12: 0000000000401850 > > R13: 00000000004018e0 R14: 0000000000000000 R15: 0000000000000000 > > Dumping ftrace buffer: > > (ftrace buffer empty) > > Kernel Offset: disabled > > Rebooting in 86400 seconds.. > > > > > > --- > > This bug is generated by a bot. It may contain errors. > > See https://goo.gl/tpsmEJ for more information about syzbot. > > syzbot engineers can be reached at syzkaller@googlegroups.com. > > > > syzbot will keep track of this bug report. See: > > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > > syzbot. > > syzbot can test patches for this bug, for details see: > > https://goo.gl/tpsmEJ#testing-patches > -- Masami Hiramatsu <mhiramat@kernel.org> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: WARNING in arch_uprobe_analyze_insn 2018-05-15 14:48 ` Masami Hiramatsu @ 2018-05-15 16:18 ` Oleg Nesterov 0 siblings, 0 replies; 6+ messages in thread From: Oleg Nesterov @ 2018-05-15 16:18 UTC (permalink / raw) To: Masami Hiramatsu Cc: syzbot, bp, hpa, linux-kernel, mingo, ricardo.neri-calderon, syzkaller-bugs, tglx, x86, yhs On 05/15, Masami Hiramatsu wrote: > > On Tue, 15 May 2018 15:36:30 +0200 > Oleg Nesterov <oleg@redhat.com> wrote: > > > Unfortunately, insn_get_length() returns void, and I do not see any > > insn-was-decoded-correctly helper. Perhaps we should simply remove > > this WARN_ON() ? > > Yes, it should just return an error, OK, I'll send the fix, > since user can miss the > probe address on user binary and we can not make sure > that is on a instruction boundary. Or this insn is actually invalid. > > Alternatively, If am right we can move this check down after the "good_insns" > > checks, but this doesn't look very clean to me. > > I think it is enough if arch_uprobe_analyze_insn() returns an error. > That makes prepare_uprobe() fail and finally leads uprobe_register() > fail. I meant that this way we could probably keep WARN_ON(). Nevermind. Thanks! Oleg. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() 2018-05-14 14:24 WARNING in arch_uprobe_analyze_insn syzbot 2018-05-15 13:36 ` Oleg Nesterov @ 2018-05-18 16:27 ` Oleg Nesterov 2018-05-18 23:58 ` Masami Hiramatsu 1 sibling, 1 reply; 6+ messages in thread From: Oleg Nesterov @ 2018-05-18 16:27 UTC (permalink / raw) To: Ingo Molnar; +Cc: linux-kernel, syzkaller-bugs, syzbot, Masami Hiramatsu insn_get_length() has the side-effect of processing the entire instruction but only if it was decoded successfully, otherwise insn_complete() can fail and in this case we need to just return an error without warning. Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- arch/x86/kernel/uprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 85c7ef2..efd7ee9 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -293,7 +293,7 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64); /* has the side-effect of processing the entire instruction */ insn_get_length(insn); - if (WARN_ON_ONCE(!insn_complete(insn))) + if (!insn_complete(insn)) return -ENOEXEC; if (is_prefix_bad(insn)) -- 2.5.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() 2018-05-18 16:27 ` [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() Oleg Nesterov @ 2018-05-18 23:58 ` Masami Hiramatsu 0 siblings, 0 replies; 6+ messages in thread From: Masami Hiramatsu @ 2018-05-18 23:58 UTC (permalink / raw) To: Oleg Nesterov Cc: Ingo Molnar, linux-kernel, syzkaller-bugs, syzbot, Masami Hiramatsu On Fri, 18 May 2018 18:27:39 +0200 Oleg Nesterov <oleg@redhat.com> wrote: > insn_get_length() has the side-effect of processing the entire instruction > but only if it was decoded successfully, otherwise insn_complete() can fail > and in this case we need to just return an error without warning. > This looks good to me. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Thanks! > Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > arch/x86/kernel/uprobes.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c > index 85c7ef2..efd7ee9 100644 > --- a/arch/x86/kernel/uprobes.c > +++ b/arch/x86/kernel/uprobes.c > @@ -293,7 +293,7 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool > insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64); > /* has the side-effect of processing the entire instruction */ > insn_get_length(insn); > - if (WARN_ON_ONCE(!insn_complete(insn))) > + if (!insn_complete(insn)) > return -ENOEXEC; > > if (is_prefix_bad(insn)) > -- > 2.5.0 > > -- Masami Hiramatsu <mhiramat@kernel.org> ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-05-18 23:58 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-05-14 14:24 WARNING in arch_uprobe_analyze_insn syzbot 2018-05-15 13:36 ` Oleg Nesterov 2018-05-15 14:48 ` Masami Hiramatsu 2018-05-15 16:18 ` Oleg Nesterov 2018-05-18 16:27 ` [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() Oleg Nesterov 2018-05-18 23:58 ` Masami Hiramatsu
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