Re: [PATCH -tip v6 00/22] kprobes: introduce NOKPROBE_SYMBOL(), cleanup and fixes crash bugs

[Frank Ch. Eigler]

Hi -

mingo wrote:
> [...]
> For example a hash table (hashed by probe address) could be used in 
> addition to the list, to speed up basic operations.

In the past, when this sort of behavior popped up, it was due to
machine-wide halt/sync operations being done too eagerly.  At one
point, the kprobes-unregistration interface grew a mass-unregister API
to batch them (and save the machine sync's between operations).  Maybe
with the new checks/logic, a similar batching API may be needed for
the registration side.

I'll try to get more perf data once the VM comes back up; after a
couple of hours of the test getting started, it died (for possibly
unrelated reasons).


[  133.073670] stap_bc6054113aa63134d411836da0afefc3_123_1261: module verification failed: signature and/or  required key missing - tainting kernel
[  404.357210] stap_4c53547addc9f25dd87ac4afa0407ed6_36_1948: systemtap: 2.5/0.157, base: ffffffffa0201000, memory: 15882data/24text/1ctx/2058net/4625alloc kb, probes: 34692
[ 1655.745075] hrtimer: interrupt took 1225946 ns
[ 3969.175039] [sched_delayed] sched: RT throttling activated
[10812.665534] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
[10812.665534] BUG: unable to handle kernel paging request at ffff88007902f038
[10812.665534] IP: [<ffff88007902f038>] 0xffff88007902f038
[10812.665534] PGD 2d90067 PUD 2d93067 PMD 80000000790001e3 
[10812.665534] Oops: 0010 [#1] SMP 
[10812.665534] Modules linked in: stap_4c53547addc9f25dd87ac4afa0407ed6_36_1948(OF) rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd sunrpc fscache ppdev microcode parport_pc parport i2c_piix4 virtio_balloon i2c_core serio_raw virtio_net virtio_pci ata_generic virtio_ring pata_acpi virtio [last unloaded: stap_89fcd2b984e11a30dd08d141e6b47e13_123_1681]
[10812.665534] CPU: 1 PID: -30720 Comm: <F8><A1><D0>x Tainted: GF          O 3.13.0-rc4-01828-g8b349c29efae #1
[10812.665534] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[10812.665534] BUG: unable to handle kernel paging request at 000000008f896e09
[10812.665534] IP: [<ffffffff810d9f55>] do_raw_spin_trylock+0x5/0x60
[10812.665534] PGD 0 
[10812.665534] Thread overran stack, or stack corrupted
[10812.665534] Oops: 0000 [#2] SMP 
[10812.665534] Modules linked in: stap_4c53547addc9f25dd87ac4afa0407ed6_36_1948(OF) rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd sunrpc fscache ppdev microcode parport_pc parport i2c_piix4 virtio_balloon i2c_core serio_raw virtio_net virtio_pci ata_generic virtio_ring pata_acpi virtio [last unloaded: stap_89fcd2b984e11a30dd08d141e6b47e13_123_1681]
[10812.665534] CPU: 1 PID: -30720 Comm: <F8><A1><D0>x Tainted: GF          O 3.13.0-rc4-01828-g8b349c29efae #1
[10812.665534] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[10812.665534] BUG: unable to handle kernel paging request at 000000008f896e09
[10812.665534] IP: [<ffffffff810d9f55>] do_raw_spin_trylock+0x5/0x60
[10812.665534] PGD 0 
[10812.665534] Thread overran stack, or stack corrupted
[10812.665534] Oops: 0000 [#3] SMP 
[10812.665534] Modules linked in: stap_4c53547addc9f25dd87ac4afa0407ed6_36_1948(OF) rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd sunrpc fscache ppdev microcode parport_pc parport i2c_piix4 virtio_balloon i2c_core serio_raw virtio_net virtio_pci ata_generic virtio_ring pata_acpi virtio [last unloaded: stap_89fcd2b984e11a30dd08d141e6b47e13_123_1681]
[10812.665534] CPU: 1 PID: -30720 Comm: <F8><A1><D0>x Tainted: GF          O 3.13.0-rc4-01828-g8b349c29efae #1
[10812.665534] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[10812.665534] BUG: unable to handle kernel paging request at 000000008f896e09
[10812.665534] IP: [<ffffffff810d9f55>] do_raw_spin_trylock+0x5/0x60
[10812.665534] PGD 0 
[10812.665534] Thread overran stack, or stack corrupted
[10812.665534] Oops: 0000 [#4] SMP 
[10812.665534] Modules linked in: stap_4c53547addc9f25dd87ac4afa0407ed6_36_1948(OF) rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd sunrpc fscache ppdev microcode parport_pc parport i2c_piix4 virtio_balloon i2c_core serio_raw virtio_net virtio_pci ata_generic virtio_ring pata_acpi virtio [last unloaded: stap_89fcd2b984e11a30dd08d141e6b47e13_123_1681]
[10812.665534] CPU: 1 PID: -30720 Comm: <F8><A1><D0>x Tainted: GF          O 3.13.0-rc4-01828-g8b349c29efae #1
[10812.665534] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[10812.665534] BUG: unable to handle kernel paging request at 000000008f896e09
[10812.665534] IP: [<ffffffff810d9f55>] do_raw_spin_trylock+0x5/0x60
[10812.665534] PGD 0 
[10812.665534] Thread overran stack, or stack corrupted
[10812.665042] ------------[ cut here ]------------
[10812.665042] WARNING: CPU: 0 PID: 1948 at arch/x86/kernel/kprobes/core.c:600 reenter_kprobe+0x3c/0xd0()
[10812.665042] Modules linked in: stap_4c53547addc9f25dd87ac4afa0407ed6_36_1948(OF) rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd sunrpc fscache ppdev microcode parport_pc parport i2c_piix4 virtio_balloon i2c_core serio_raw virtio_net virtio_pci ata_generic virtio_ring pata_acpi virtio [last unloaded: stap_89fcd2b984e11a30dd08d141e6b47e13_123_1681]


- FChE
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