Hi,
Here is version 2 series of patches to support accessing function entry data
from function *return* probes (including kretprobe and fprobe-exit event).
In this version, I added another cleanup [4/7], updated README[5/7], added
testcases[6/7] and updated document[7/7].
This allows us to access the results of some functions, which returns the
error code and its results are passed via function parameter, such as an
structure-initialization function.
For example, vfs_open() will link the file structure to the inode and update
mode. Thus we can trace that changes.
# echo 'f vfs_open mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
# echo 'f vfs_open%return mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
# echo 1 > events/fprobes/enable
# cat trace
sh-131 [006] ...1. 1945.714346: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x2 inode=0x0
sh-131 [006] ...1. 1945.714358: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4d801e inode=0xffff888008470168
cat-143 [007] ...1. 1945.717949: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
cat-143 [007] ...1. 1945.717956: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4a801d inode=0xffff888005f78d28
cat-143 [007] ...1. 1945.720616: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
cat-143 [007] ...1. 1945.728263: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0xa800d inode=0xffff888004ada8d8
So as you can see those fields are initialized at exit.
This series is based on v6.8-rc5 kernel or you can checkout from
https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git/log/?h=topic/entry-data
Thank you,
---
Masami Hiramatsu (Google) (7):
tracing/fprobe-event: cleanup: Fix a wrong comment in fprobe event
tracing/probes: Cleanup probe argument parser
tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init
tracing: Remove redundant #else block for BTF args from README
tracing/probes: Support $argN in return probe (kprobe and fprobe)
selftests/ftrace: Add test cases for entry args at function exit
Documentation: tracing: Add entry argument access at function exit
Documentation/trace/fprobetrace.rst | 7
Documentation/trace/kprobetrace.rst | 7
kernel/trace/trace.c | 5
kernel/trace/trace_eprobe.c | 8
kernel/trace/trace_fprobe.c | 59 ++-
kernel/trace/trace_kprobe.c | 58 ++-
kernel/trace/trace_probe.c | 417 ++++++++++++++------
kernel/trace/trace_probe.h | 30 +
kernel/trace/trace_probe_tmpl.h | 10
kernel/trace/trace_uprobe.c | 14 -
.../ftrace/test.d/dynevent/fprobe_entry_arg.tc | 18 +
.../ftrace/test.d/kprobe/kretprobe_entry_arg.tc | 18 +
12 files changed, 483 insertions(+), 168 deletions(-)
create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_entry_arg.tc
create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_entry_arg.tc
--
Masami Hiramatsu (Google) <[email protected]>
From: Masami Hiramatsu (Google) <[email protected]>
Add a notes about the entry argument access at function exit probes for
kprobes and fprobe trace event.
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
---
Documentation/trace/fprobetrace.rst | 7 +++++++
Documentation/trace/kprobetrace.rst | 7 +++++++
2 files changed, 14 insertions(+)
diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst
index e35e6b18df40..ab71ebf178cb 100644
--- a/Documentation/trace/fprobetrace.rst
+++ b/Documentation/trace/fprobetrace.rst
@@ -70,6 +70,13 @@ Synopsis of fprobe-events
For the details of TYPE, see :ref:`kprobetrace documentation <kprobetrace_types>`.
+Function arguments at exit
+--------------------------
+Function arguments can be accessed at exit probe using $arg<N> fetcharg. This
+is useful to record the function parameter and return value at once, and
+trace the difference of structure fields (for debuging a function whether it
+correctly updates the given data structure or not)
+
BTF arguments
-------------
BTF (BPF Type Format) argument allows user to trace function and tracepoint
diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index bf9cecb69fc9..35a383f95746 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -70,6 +70,13 @@ Synopsis of kprobe_events
(\*3) this is useful for fetching a field of data structures.
(\*4) "u" means user-space dereference. See :ref:`user_mem_access`.
+Function arguments at kretprobe
+-------------------------------
+Function arguments can be accessed at kretprobe using $arg<N> fetcharg. This
+is useful to record the function parameter and return value at once, and
+trace the difference of structure fields (for debuging a function whether it
+correctly updates the given data structure or not)
+
.. _kprobetrace_types:
Types
On Mon, Feb 26, 2024 at 12:57:53PM +0900, Masami Hiramatsu (Google) wrote:
> Hi,
>
> Here is version 2 series of patches to support accessing function entry data
> from function *return* probes (including kretprobe and fprobe-exit event).
>
> In this version, I added another cleanup [4/7], updated README[5/7], added
> testcases[6/7] and updated document[7/7].
>
> This allows us to access the results of some functions, which returns the
> error code and its results are passed via function parameter, such as an
> structure-initialization function.
>
> For example, vfs_open() will link the file structure to the inode and update
> mode. Thus we can trace that changes.
>
> # echo 'f vfs_open mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
> # echo 'f vfs_open%return mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
> # echo 1 > events/fprobes/enable
> # cat trace
> sh-131 [006] ...1. 1945.714346: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x2 inode=0x0
> sh-131 [006] ...1. 1945.714358: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4d801e inode=0xffff888008470168
> cat-143 [007] ...1. 1945.717949: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
> cat-143 [007] ...1. 1945.717956: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4a801d inode=0xffff888005f78d28
> cat-143 [007] ...1. 1945.720616: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
> cat-143 [007] ...1. 1945.728263: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0xa800d inode=0xffff888004ada8d8
hi,
I hit a crash while playing with this, by runnning:
# echo 'f vfs_read%return $arg*' >> dynamic_events
# echo 1 > events/fprobes/enable
jirka
---
[ 86.805519][ T712] general protection fault, probably for non-canonical address 0xef01a20a8bd21200: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
[ 86.807259][ T712] CPU: 0 PID: 712 Comm: cat Not tainted 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
[ 86.808417][ T712] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
[ 86.809294][ T712] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.809930][ T712] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.811727][ T712] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
[ 86.812316][ T712] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
[ 86.813106][ T712] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
[ 86.813881][ T712] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
[ 86.814626][ T712] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
[ 86.815357][ T712] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
[ 86.816114][ T712] FS: 00007f22d7c1f740(0000) GS:ffff88846ce00000(0000) knlGS:0000000000000000
[ 86.816885][ T712] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.817455][ T712] CR2: 00007f22d7b9c000 CR3: 0000000176918001 CR4: 0000000000770ef0
[ 86.818221][ T712] PKRU: 55555554
[ 86.818579][ T712] Call Trace:
[ 86.818900][ T712] <TASK>
[ 86.819194][ T712] ? die_addr+0x32/0x80
[ 86.819583][ T712] ? exc_general_protection+0x276/0x4d0
[ 86.820079][ T712] ? asm_exc_general_protection+0x22/0x30
[ 86.820600][ T712] ? ksys_read+0x69/0xf0
[ 86.821022][ T712] ? ksys_read+0x69/0xf0
[ 86.821422][ T712] ? rethook_trampoline_handler+0x8e/0x200
[ 86.821984][ T712] ? rethook_trampoline_handler+0x91/0x200
[ 86.822539][ T712] arch_rethook_trampoline_callback+0x36/0x50
[ 86.823097][ T712] arch_rethook_trampoline+0x2c/0x60
[ 86.823584][ T712] ? ksys_read+0x69/0xf0
[ 86.823962][ T712] osnoise_arch_unregister+0x210/0x210
[ 86.824463][ T712] do_syscall_64+0x87/0x1b0
[ 86.824910][ T712] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 86.825418][ T712] RIP: 0033:0x7f22d7d230b1
[ 86.825859][ T712] Code: d5 fe ff ff 55 48 8d 3d 25 47 0a 00 48 89 e5 e8 b5 18 02 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d 2d b5 0d 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec
[ 86.827635][ T712] RSP: 002b:00007fffdaaef668 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 86.828355][ T712] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f22d7d230b1
[ 86.829017][ T712] RDX: 0000000000020000 RSI: 00007f22d7b9c000 RDI: 0000000000000003
[ 86.829710][ T712] RBP: 00007fffdaaef690 R08: 00000000ffffffff R09: 0000000000000000
[ 86.831165][ T712] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000020000
[ 86.831910][ T712] R13: 00007f22d7b9c000 R14: 0000000000000003 R15: 0000000000000000
[ 86.832691][ T712] </TASK>
[ 86.833016][ T712] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
[ 86.835078][ T634] general protection fault, probably for non-canonical address 0x440038d965baf00: 0000 [#2] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
[ 86.835196][ T712] ---[ end trace 0000000000000000 ]---
[ 86.835943][ T634] CPU: 3 PID: 634 Comm: sshd Tainted: G D 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
[ 86.835946][ T634] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
[ 86.835947][ T634] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.835952][ T634] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.836363][ T712] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.837090][ T634] RSP: 0018:ffffc90001d3bdf8 EFLAGS: 00010206
[ 86.837776][ T712] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.838205][ T634]
[ 86.839488][ T712] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
[ 86.839890][ T634] RAX: ffffc90001d3bef0 RBX: ffff888176cbbaa0 RCX: ffffc90001d3be40
[ 86.840239][ T712]
[ 86.840240][ T712] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
[ 86.841309][ T634] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888176cbba90
[ 86.841311][ T634] RBP: ffff888176cbbaa0 R08: 0000000000000001 R09: 0000000000000000
[ 86.841312][ T634] R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff81545129
[ 86.841313][ T634] R13: 0440038d965baf00 R14: ffffc90001d3bee8 R15: ffffc90001d3be40
[ 86.841314][ T634] FS: 00007f1ddf838940(0000) GS:ffff88846da00000(0000) knlGS:0000000000000000
[ 86.841316][ T634] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.841477][ T712] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
[ 86.841800][ T634] CR2: 0000559fb5f9f000 CR3: 0000000176e2e004 CR4: 0000000000770ef0
[ 86.842308][ T712] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
[ 86.842456][ T634] PKRU: 55555554
[ 86.842458][ T634] Call Trace:
[ 86.842459][ T634] <TASK>
[ 86.842462][ T634] ? die_addr+0x32/0x80
[ 86.842978][ T712] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
[ 86.843508][ T634] ? exc_general_protection+0x276/0x4d0
[ 86.843516][ T634] ? asm_exc_general_protection+0x22/0x30
[ 86.844002][ T712] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
[ 86.844004][ T712] FS: 00007f22d7c1f740(0000) GS:ffff88846ce00000(0000) knlGS:0000000000000000
[ 86.844503][ T634] ? ksys_read+0x69/0xf0
[ 86.844507][ T634] ? ksys_read+0x69/0xf0
[ 86.844510][ T634] ? rethook_trampoline_handler+0x8e/0x200
[ 86.845033][ T712] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.845677][ T634] ? rethook_trampoline_handler+0x91/0x200
[ 86.845680][ T634] arch_rethook_trampoline_callback+0x36/0x50
[ 86.845684][ T634] arch_rethook_trampoline+0x2c/0x60
[ 86.846111][ T712] CR2: 00007f22d7b9c000 CR3: 0000000176918001 CR4: 0000000000770ef0
[ 86.846674][ T634] ? ksys_read+0x69/0xf0
[ 86.846679][ T634] osnoise_arch_unregister+0x210/0x210
[ 86.847213][ T712] PKRU: 55555554
[ 86.847648][ T634] do_syscall_64+0x87/0x1b0
[ 86.847653][ T634] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 86.847868][ T712] note: cat[712] exited with preempt_count 1
[ 86.848096][ T634] RIP: 0033:0x7f1ddfc4a0b1
[ 86.869351][ T634] Code: d5 fe ff ff 55 48 8d 3d 25 47 0a 00 48 89 e5 e8 b5 18 02 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d 2d b5 0d 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec
[ 86.871186][ T634] RSP: 002b:00007fffdd061ae8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 86.871995][ T634] RAX: ffffffffffffffda RBX: 0000000000008000 RCX: 00007f1ddfc4a0b1
[ 86.872785][ T634] RDX: 0000000000008000 RSI: 000055bbb41e37b0 RDI: 000000000000000c
[ 86.873553][ T634] RBP: 00007fffdd061b50 R08: 0000000000000000 R09: 0000000000000000
[ 86.874320][ T634] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
[ 86.874960][ T634] R13: 0000000000000000 R14: 000055bbb4172840 R15: 000000000000000c
[ 86.875670][ T634] </TASK>
[ 86.875964][ T634] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
[ 86.877814][ T634] ---[ end trace 0000000000000000 ]---
[ 86.877991][ T450] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
[ 86.878210][ T634] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.878217][ T634] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.878219][ T634] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
[ 86.878221][ T634] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
[ 86.878222][ T634] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
[ 86.878224][ T634] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
[ 86.878225][ T634] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
[ 86.878226][ T634] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
[ 86.878227][ T634] FS: 00007f1ddf838940(0000) GS:ffff88846da00000(0000) knlGS:0000000000000000
[ 86.878228][ T634] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.878230][ T634] CR2: 0000559fb5f9f000 CR3: 0000000176e2e004 CR4: 0000000000770ef0
[ 86.878233][ T634] PKRU: 55555554
[ 86.878235][ T634] note: sshd[634] exited with preempt_count 1
[ 86.888492][ T450] BUG: unable to handle page fault for address: ffffc90001cdff58
[ 86.889266][ T450] #PF: supervisor instruction fetch in kernel mode
[ 86.889914][ T450] #PF: error_code(0x0011) - permissions violation
[ 86.891248][ T450] PGD 100000067 P4D 100000067 PUD 102a49067 PMD 10b3ee067 PTE 8000000109295163
[ 86.892032][ T450] Oops: 0011 [#3] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
[ 86.892560][ T450] CPU: 1 PID: 450 Comm: systemd-journal Tainted: G D 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
[ 86.893758][ T450] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
[ 86.894542][ T450] RIP: 0010:0xffffc90001cdff58
[ 86.894964][ T450] Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e6 00 60 82 ff ff ff ff <00> 00 00 00 00 00 00 00 03 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 86.896519][ T450] RSP: 0018:ffffc90000b13df0 EFLAGS: 00010282
[ 86.897004][ T450] RAX: ffffc90001cdfef0 RBX: ffff88817759a8a0 RCX: ffffc90000b13e40
[ 86.897672][ T450] RDX: ffffffff81545129 RSI: ffffffffffffffff RDI: ffff88817759a890
[ 86.898341][ T450] RBP: ffff88817759a8a0 R08: 0000000000000001 R09: ffff888102b2c470
[ 86.899143][ T450] R10: ffffc90000b13e58 R11: ffffffff83976548 R12: ffffffff81545129
[ 86.899871][ T450] R13: ffffc90001cdff58 R14: ffffc90000b13ee8 R15: ffffc90000b13e40
[ 86.900547][ T450] FS: 00007f20a7635940(0000) GS:ffff88846d200000(0000) knlGS:0000000000000000
[ 86.901259][ T450] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.901773][ T450] CR2: ffffc90001cdff58 CR3: 0000000176a7a003 CR4: 0000000000770ef0
[ 86.902411][ T450] PKRU: 55555554
[ 86.902722][ T450] Call Trace:
[ 86.903009][ T450] <TASK>
[ 86.903271][ T450] ? __die+0x1f/0x70
[ 86.903613][ T450] ? page_fault_oops+0x176/0x4d0
[ 86.904126][ T450] ? exc_page_fault+0x16c/0x250
[ 86.904614][ T450] ? asm_exc_page_fault+0x22/0x30
[ 86.905140][ T450] ? ksys_read+0x69/0xf0
[ 86.905615][ T450] ? ksys_read+0x69/0xf0
[ 86.906053][ T450] ? rethook_trampoline_handler+0x91/0x200
[ 86.906643][ T450] ? arch_rethook_trampoline_callback+0x36/0x50
[ 86.907271][ T450] ? arch_rethook_trampoline+0x2c/0x60
[ 86.907845][ T450] ? ksys_read+0x69/0xf0
[ 86.908300][ T450] ? osnoise_arch_unregister+0x210/0x210
[ 86.908781][ T450] ? do_syscall_64+0x87/0x1b0
[ 86.909186][ T450] ? entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 86.909681][ T450] </TASK>
[ 86.909959][ T450] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
[ 86.911681][ T450] CR2: ffffc90001cdff58
[ 86.912108][ T450] ---[ end trace 0000000000000000 ]---
[ 86.912674][ T450] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.913232][ T450] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.914702][ T450] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
[ 86.915196][ T450] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
[ 86.915853][ T450] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
[ 86.916644][ T450] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
[ 86.917449][ T450] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
[ 86.918238][ T450] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
[ 86.919043][ T450] FS: 00007f20a7635940(0000) GS:ffff88846d200000(0000) knlGS:0000000000000000
[ 86.919906][ T450] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.921265][ T450] CR2: ffffc90001cdff58 CR3: 0000000176a7a003 CR4: 0000000000770ef0
[ 86.921972][ T450] PKRU: 55555554
[ 86.922365][ T450] note: systemd-journal[450] exited with irqs disabled
[ 86.923076][ T450] note: systemd-journal[450] exited with preempt_count 1
[ 86.927597][ T47] audit: type=1106 audit(1709132147.391:266): pid=619 uid=0 auid=1000 ses=1 subj=system_u:system_r:sshd_t:s0-s0:c0.c1023 msg='op=PAM:session_close grantors=pam_selinux,pam_loginuid,pam_selinux,pam_namespace,pam_keyinit,pam_keyinit,pam_limits,pam_systemd,pam_unix,pam_umask,pam_lastlog acct="jolsa" exe="/usr/sbin/sshd" hostname=192.168.122.1 addr=192.168.122.1 terminal=ssh res=success'
[ 86.928777][ T450] systemd-journal (450) used greatest stack depth: 11424 bytes left
[ 86.929578][ T1] general protection fault, probably for non-canonical address 0xd4f06e07d9d64800: 0000 [#4] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
[ 86.929582][ T1] CPU: 2 PID: 1 Comm: systemd Tainted: G D 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
[ 86.929584][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
[ 86.929586][ T1] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.929591][ T1] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.929592][ T1] RSP: 0018:ffffc90000013df8 EFLAGS: 00010286
[ 86.929594][ T1] RAX: ffffc90000013ef0 RBX: ffff888177598aa0 RCX: ffffc90000013e40
[ 86.929595][ T1] RDX: ffffffff81545129 RSI: 0000000000000010 RDI: ffff888177598a90
[ 86.929596][ T1] RBP: ffff888177598aa0 R08: 0000000000000010 R09: ffff888175005750
[ 86.929597][ T1] R10: 0000000000000000 R11: ffffc90000013dd8 R12: ffffffff81545129
[ 86.929598][ T1] R13: d4f06e07d9d64800 R14: ffffc90000013ee8 R15: ffffc90000013e40
[ 86.929599][ T1] FS: 00007f0ec5012940(0000) GS:ffff88846d600000(0000) knlGS:0000000000000000
[ 86.929600][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.929601][ T1] CR2: 00005595e83bf5b0 CR3: 000000010805e001 CR4: 0000000000770ef0
[ 86.929604][ T1] PKRU: 55555554
[ 86.929605][ T1] Call Trace:
[ 86.929606][ T1] <TASK>
[ 86.929606][ T1] ? die_addr+0x32/0x80
[ 86.929610][ T1] ? exc_general_protection+0x276/0x4d0
[ 86.929616][ T1] ? asm_exc_general_protection+0x22/0x30
[ 86.929621][ T1] ? ksys_read+0x69/0xf0
[ 86.929624][ T1] ? ksys_read+0x69/0xf0
[ 86.929627][ T1] ? rethook_trampoline_handler+0x8e/0x200
[ 86.929629][ T1] ? rethook_trampoline_handler+0x91/0x200
[ 86.929631][ T1] arch_rethook_trampoline_callback+0x36/0x50
[ 86.929635][ T1] arch_rethook_trampoline+0x2c/0x60
[ 86.929639][ T1] ? ksys_read+0x69/0xf0
[ 86.929640][ T1] osnoise_arch_unregister+0x210/0x210
[ 86.929643][ T1] do_syscall_64+0x87/0x1b0
[ 86.929645][ T1] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 86.929647][ T1] RIP: 0033:0x7f0ec49230ea
[ 86.929653][ T1] Code: 55 48 89 e5 48 83 ec 20 48 89 55 e8 48 89 75 f0 89 7d f8 e8 e8 79 f8 ff 48 8b 55 e8 48 8b 75 f0 41 89 c0 8b 7d f8 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 2e 44 89 c7 48 89 45 f8 e8 42 7a f8 ff 48 8b
[ 86.929655][ T1] RSP: 002b:00007ffead1dc7a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 86.929656][ T1] RAX: ffffffffffffffda RBX: 00005625bff4efe0 RCX: 00007f0ec49230ea
[ 86.929657][ T1] RDX: 0000000000000400 RSI: 00005625bfeda010 RDI: 0000000000000019
[ 86.929658][ T1] RBP: 00007ffead1dc7c0 R08: 0000000000000000 R09: 0000000000000001
[ 86.929659][ T1] R10: 0000000000001000 R11: 0000000000000246 R12: 00007f0ec49f3660
[ 86.929659][ T1] R13: 00007f0ec50127d0 R14: 0000000000000a68 R15: 00007f0ec49f2d60
[ 86.929663][ T1] </TASK>
[ 86.929663][ T1] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
[ 86.929676][ T1] ---[ end trace 0000000000000000 ]---
[ 86.929677][ T1] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
[ 86.929679][ T1] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
[ 86.929680][ T1] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
[ 86.929681][ T1] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
[ 86.929682][ T1] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
[ 86.929683][ T1] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
[ 86.929684][ T1] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
[ 86.929685][ T1] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
[ 86.929686][ T1] FS: 00007f0ec5012940(0000) GS:ffff88846d600000(0000) knlGS:0000000000000000
[ 86.929687][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 86.929688][ T1] CR2: 00005595e83bf5b0 CR3: 000000010805e001 CR4: 0000000000770ef0
[ 86.929688][ T1] PKRU: 55555554
[ 86.929689][ T1] note: systemd[1] exited with preempt_count 1
[ 86.929692][ T1] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[ 86.929992][ T1] Kernel Offset: disabled
On Wed, 28 Feb 2024 17:23:34 +0100
Jiri Olsa <[email protected]> wrote:
> On Mon, Feb 26, 2024 at 12:57:53PM +0900, Masami Hiramatsu (Google) wrote:
> > Hi,
> >
> > Here is version 2 series of patches to support accessing function entry data
> > from function *return* probes (including kretprobe and fprobe-exit event).
> >
> > In this version, I added another cleanup [4/7], updated README[5/7], added
> > testcases[6/7] and updated document[7/7].
> >
> > This allows us to access the results of some functions, which returns the
> > error code and its results are passed via function parameter, such as an
> > structure-initialization function.
> >
> > For example, vfs_open() will link the file structure to the inode and update
> > mode. Thus we can trace that changes.
> >
> > # echo 'f vfs_open mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
> > # echo 'f vfs_open%return mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
> > # echo 1 > events/fprobes/enable
> > # cat trace
> > sh-131 [006] ...1. 1945.714346: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x2 inode=0x0
> > sh-131 [006] ...1. 1945.714358: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4d801e inode=0xffff888008470168
> > cat-143 [007] ...1. 1945.717949: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
> > cat-143 [007] ...1. 1945.717956: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4a801d inode=0xffff888005f78d28
> > cat-143 [007] ...1. 1945.720616: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
> > cat-143 [007] ...1. 1945.728263: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0xa800d inode=0xffff888004ada8d8
>
> hi,
> I hit a crash while playing with this, by runnning:
>
> # echo 'f vfs_read%return $arg*' >> dynamic_events
> # echo 1 > events/fprobes/enable
Thanks for reporting! But I can not reproduce it.
Can you share your kconfig?
>
> jirka
>
>
> ---
> [ 86.805519][ T712] general protection fault, probably for non-canonical address 0xef01a20a8bd21200: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
> [ 86.807259][ T712] CPU: 0 PID: 712 Comm: cat Not tainted 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
> [ 86.808417][ T712] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
> [ 86.809294][ T712] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.809930][ T712] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.811727][ T712] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
> [ 86.812316][ T712] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
> [ 86.813106][ T712] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
> [ 86.813881][ T712] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
> [ 86.814626][ T712] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
> [ 86.815357][ T712] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
> [ 86.816114][ T712] FS: 00007f22d7c1f740(0000) GS:ffff88846ce00000(0000) knlGS:0000000000000000
> [ 86.816885][ T712] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.817455][ T712] CR2: 00007f22d7b9c000 CR3: 0000000176918001 CR4: 0000000000770ef0
> [ 86.818221][ T712] PKRU: 55555554
> [ 86.818579][ T712] Call Trace:
> [ 86.818900][ T712] <TASK>
> [ 86.819194][ T712] ? die_addr+0x32/0x80
> [ 86.819583][ T712] ? exc_general_protection+0x276/0x4d0
> [ 86.820079][ T712] ? asm_exc_general_protection+0x22/0x30
> [ 86.820600][ T712] ? ksys_read+0x69/0xf0
> [ 86.821022][ T712] ? ksys_read+0x69/0xf0
> [ 86.821422][ T712] ? rethook_trampoline_handler+0x8e/0x200
> [ 86.821984][ T712] ? rethook_trampoline_handler+0x91/0x200
> [ 86.822539][ T712] arch_rethook_trampoline_callback+0x36/0x50
> [ 86.823097][ T712] arch_rethook_trampoline+0x2c/0x60
> [ 86.823584][ T712] ? ksys_read+0x69/0xf0
> [ 86.823962][ T712] osnoise_arch_unregister+0x210/0x210
> [ 86.824463][ T712] do_syscall_64+0x87/0x1b0
> [ 86.824910][ T712] entry_SYSCALL_64_after_hwframe+0x6e/0x76
> [ 86.825418][ T712] RIP: 0033:0x7f22d7d230b1
> [ 86.825859][ T712] Code: d5 fe ff ff 55 48 8d 3d 25 47 0a 00 48 89 e5 e8 b5 18 02 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d 2d b5 0d 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec
> [ 86.827635][ T712] RSP: 002b:00007fffdaaef668 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> [ 86.828355][ T712] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f22d7d230b1
> [ 86.829017][ T712] RDX: 0000000000020000 RSI: 00007f22d7b9c000 RDI: 0000000000000003
> [ 86.829710][ T712] RBP: 00007fffdaaef690 R08: 00000000ffffffff R09: 0000000000000000
> [ 86.831165][ T712] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000020000
> [ 86.831910][ T712] R13: 00007f22d7b9c000 R14: 0000000000000003 R15: 0000000000000000
> [ 86.832691][ T712] </TASK>
> [ 86.833016][ T712] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
> [ 86.835078][ T634] general protection fault, probably for non-canonical address 0x440038d965baf00: 0000 [#2] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
> [ 86.835196][ T712] ---[ end trace 0000000000000000 ]---
> [ 86.835943][ T634] CPU: 3 PID: 634 Comm: sshd Tainted: G D 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
> [ 86.835946][ T634] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
> [ 86.835947][ T634] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.835952][ T634] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.836363][ T712] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.837090][ T634] RSP: 0018:ffffc90001d3bdf8 EFLAGS: 00010206
> [ 86.837776][ T712] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.838205][ T634]
> [ 86.839488][ T712] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
> [ 86.839890][ T634] RAX: ffffc90001d3bef0 RBX: ffff888176cbbaa0 RCX: ffffc90001d3be40
> [ 86.840239][ T712]
> [ 86.840240][ T712] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
> [ 86.841309][ T634] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888176cbba90
> [ 86.841311][ T634] RBP: ffff888176cbbaa0 R08: 0000000000000001 R09: 0000000000000000
> [ 86.841312][ T634] R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff81545129
> [ 86.841313][ T634] R13: 0440038d965baf00 R14: ffffc90001d3bee8 R15: ffffc90001d3be40
> [ 86.841314][ T634] FS: 00007f1ddf838940(0000) GS:ffff88846da00000(0000) knlGS:0000000000000000
> [ 86.841316][ T634] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.841477][ T712] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
> [ 86.841800][ T634] CR2: 0000559fb5f9f000 CR3: 0000000176e2e004 CR4: 0000000000770ef0
> [ 86.842308][ T712] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
> [ 86.842456][ T634] PKRU: 55555554
> [ 86.842458][ T634] Call Trace:
> [ 86.842459][ T634] <TASK>
> [ 86.842462][ T634] ? die_addr+0x32/0x80
> [ 86.842978][ T712] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
> [ 86.843508][ T634] ? exc_general_protection+0x276/0x4d0
> [ 86.843516][ T634] ? asm_exc_general_protection+0x22/0x30
> [ 86.844002][ T712] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
> [ 86.844004][ T712] FS: 00007f22d7c1f740(0000) GS:ffff88846ce00000(0000) knlGS:0000000000000000
> [ 86.844503][ T634] ? ksys_read+0x69/0xf0
> [ 86.844507][ T634] ? ksys_read+0x69/0xf0
> [ 86.844510][ T634] ? rethook_trampoline_handler+0x8e/0x200
> [ 86.845033][ T712] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.845677][ T634] ? rethook_trampoline_handler+0x91/0x200
> [ 86.845680][ T634] arch_rethook_trampoline_callback+0x36/0x50
> [ 86.845684][ T634] arch_rethook_trampoline+0x2c/0x60
> [ 86.846111][ T712] CR2: 00007f22d7b9c000 CR3: 0000000176918001 CR4: 0000000000770ef0
> [ 86.846674][ T634] ? ksys_read+0x69/0xf0
> [ 86.846679][ T634] osnoise_arch_unregister+0x210/0x210
> [ 86.847213][ T712] PKRU: 55555554
> [ 86.847648][ T634] do_syscall_64+0x87/0x1b0
> [ 86.847653][ T634] entry_SYSCALL_64_after_hwframe+0x6e/0x76
> [ 86.847868][ T712] note: cat[712] exited with preempt_count 1
> [ 86.848096][ T634] RIP: 0033:0x7f1ddfc4a0b1
> [ 86.869351][ T634] Code: d5 fe ff ff 55 48 8d 3d 25 47 0a 00 48 89 e5 e8 b5 18 02 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d 2d b5 0d 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec
> [ 86.871186][ T634] RSP: 002b:00007fffdd061ae8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> [ 86.871995][ T634] RAX: ffffffffffffffda RBX: 0000000000008000 RCX: 00007f1ddfc4a0b1
> [ 86.872785][ T634] RDX: 0000000000008000 RSI: 000055bbb41e37b0 RDI: 000000000000000c
> [ 86.873553][ T634] RBP: 00007fffdd061b50 R08: 0000000000000000 R09: 0000000000000000
> [ 86.874320][ T634] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
> [ 86.874960][ T634] R13: 0000000000000000 R14: 000055bbb4172840 R15: 000000000000000c
> [ 86.875670][ T634] </TASK>
> [ 86.875964][ T634] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
> [ 86.877814][ T634] ---[ end trace 0000000000000000 ]---
> [ 86.877991][ T450] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
> [ 86.878210][ T634] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.878217][ T634] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.878219][ T634] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
> [ 86.878221][ T634] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
> [ 86.878222][ T634] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
> [ 86.878224][ T634] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
> [ 86.878225][ T634] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
> [ 86.878226][ T634] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
> [ 86.878227][ T634] FS: 00007f1ddf838940(0000) GS:ffff88846da00000(0000) knlGS:0000000000000000
> [ 86.878228][ T634] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.878230][ T634] CR2: 0000559fb5f9f000 CR3: 0000000176e2e004 CR4: 0000000000770ef0
> [ 86.878233][ T634] PKRU: 55555554
> [ 86.878235][ T634] note: sshd[634] exited with preempt_count 1
> [ 86.888492][ T450] BUG: unable to handle page fault for address: ffffc90001cdff58
> [ 86.889266][ T450] #PF: supervisor instruction fetch in kernel mode
> [ 86.889914][ T450] #PF: error_code(0x0011) - permissions violation
> [ 86.891248][ T450] PGD 100000067 P4D 100000067 PUD 102a49067 PMD 10b3ee067 PTE 8000000109295163
> [ 86.892032][ T450] Oops: 0011 [#3] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
> [ 86.892560][ T450] CPU: 1 PID: 450 Comm: systemd-journal Tainted: G D 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
> [ 86.893758][ T450] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
> [ 86.894542][ T450] RIP: 0010:0xffffc90001cdff58
> [ 86.894964][ T450] Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e6 00 60 82 ff ff ff ff <00> 00 00 00 00 00 00 00 03 00 00 00 00 00 00 00 00 00 00 00 00 00
> [ 86.896519][ T450] RSP: 0018:ffffc90000b13df0 EFLAGS: 00010282
> [ 86.897004][ T450] RAX: ffffc90001cdfef0 RBX: ffff88817759a8a0 RCX: ffffc90000b13e40
> [ 86.897672][ T450] RDX: ffffffff81545129 RSI: ffffffffffffffff RDI: ffff88817759a890
> [ 86.898341][ T450] RBP: ffff88817759a8a0 R08: 0000000000000001 R09: ffff888102b2c470
> [ 86.899143][ T450] R10: ffffc90000b13e58 R11: ffffffff83976548 R12: ffffffff81545129
> [ 86.899871][ T450] R13: ffffc90001cdff58 R14: ffffc90000b13ee8 R15: ffffc90000b13e40
> [ 86.900547][ T450] FS: 00007f20a7635940(0000) GS:ffff88846d200000(0000) knlGS:0000000000000000
> [ 86.901259][ T450] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.901773][ T450] CR2: ffffc90001cdff58 CR3: 0000000176a7a003 CR4: 0000000000770ef0
> [ 86.902411][ T450] PKRU: 55555554
> [ 86.902722][ T450] Call Trace:
> [ 86.903009][ T450] <TASK>
> [ 86.903271][ T450] ? __die+0x1f/0x70
> [ 86.903613][ T450] ? page_fault_oops+0x176/0x4d0
> [ 86.904126][ T450] ? exc_page_fault+0x16c/0x250
> [ 86.904614][ T450] ? asm_exc_page_fault+0x22/0x30
> [ 86.905140][ T450] ? ksys_read+0x69/0xf0
> [ 86.905615][ T450] ? ksys_read+0x69/0xf0
> [ 86.906053][ T450] ? rethook_trampoline_handler+0x91/0x200
> [ 86.906643][ T450] ? arch_rethook_trampoline_callback+0x36/0x50
> [ 86.907271][ T450] ? arch_rethook_trampoline+0x2c/0x60
> [ 86.907845][ T450] ? ksys_read+0x69/0xf0
> [ 86.908300][ T450] ? osnoise_arch_unregister+0x210/0x210
> [ 86.908781][ T450] ? do_syscall_64+0x87/0x1b0
> [ 86.909186][ T450] ? entry_SYSCALL_64_after_hwframe+0x6e/0x76
> [ 86.909681][ T450] </TASK>
> [ 86.909959][ T450] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
> [ 86.911681][ T450] CR2: ffffc90001cdff58
> [ 86.912108][ T450] ---[ end trace 0000000000000000 ]---
> [ 86.912674][ T450] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.913232][ T450] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.914702][ T450] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
> [ 86.915196][ T450] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
> [ 86.915853][ T450] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
> [ 86.916644][ T450] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
> [ 86.917449][ T450] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
> [ 86.918238][ T450] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
> [ 86.919043][ T450] FS: 00007f20a7635940(0000) GS:ffff88846d200000(0000) knlGS:0000000000000000
> [ 86.919906][ T450] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.921265][ T450] CR2: ffffc90001cdff58 CR3: 0000000176a7a003 CR4: 0000000000770ef0
> [ 86.921972][ T450] PKRU: 55555554
> [ 86.922365][ T450] note: systemd-journal[450] exited with irqs disabled
> [ 86.923076][ T450] note: systemd-journal[450] exited with preempt_count 1
> [ 86.927597][ T47] audit: type=1106 audit(1709132147.391:266): pid=619 uid=0 auid=1000 ses=1 subj=system_u:system_r:sshd_t:s0-s0:c0.c1023 msg='op=PAM:session_close grantors=pam_selinux,pam_loginuid,pam_selinux,pam_namespace,pam_keyinit,pam_keyinit,pam_limits,pam_systemd,pam_unix,pam_umask,pam_lastlog acct="jolsa" exe="/usr/sbin/sshd" hostname=192.168.122.1 addr=192.168.122.1 terminal=ssh res=success'
> [ 86.928777][ T450] systemd-journal (450) used greatest stack depth: 11424 bytes left
> [ 86.929578][ T1] general protection fault, probably for non-canonical address 0xd4f06e07d9d64800: 0000 [#4] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
> [ 86.929582][ T1] CPU: 2 PID: 1 Comm: systemd Tainted: G D 6.8.0-rc5+ #432 b8184d32457f2dd20b7178757a1fce97b3f847e2
> [ 86.929584][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
> [ 86.929586][ T1] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.929591][ T1] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.929592][ T1] RSP: 0018:ffffc90000013df8 EFLAGS: 00010286
> [ 86.929594][ T1] RAX: ffffc90000013ef0 RBX: ffff888177598aa0 RCX: ffffc90000013e40
> [ 86.929595][ T1] RDX: ffffffff81545129 RSI: 0000000000000010 RDI: ffff888177598a90
> [ 86.929596][ T1] RBP: ffff888177598aa0 R08: 0000000000000010 R09: ffff888175005750
> [ 86.929597][ T1] R10: 0000000000000000 R11: ffffc90000013dd8 R12: ffffffff81545129
> [ 86.929598][ T1] R13: d4f06e07d9d64800 R14: ffffc90000013ee8 R15: ffffc90000013e40
> [ 86.929599][ T1] FS: 00007f0ec5012940(0000) GS:ffff88846d600000(0000) knlGS:0000000000000000
> [ 86.929600][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.929601][ T1] CR2: 00005595e83bf5b0 CR3: 000000010805e001 CR4: 0000000000770ef0
> [ 86.929604][ T1] PKRU: 55555554
> [ 86.929605][ T1] Call Trace:
> [ 86.929606][ T1] <TASK>
> [ 86.929606][ T1] ? die_addr+0x32/0x80
> [ 86.929610][ T1] ? exc_general_protection+0x276/0x4d0
> [ 86.929616][ T1] ? asm_exc_general_protection+0x22/0x30
> [ 86.929621][ T1] ? ksys_read+0x69/0xf0
> [ 86.929624][ T1] ? ksys_read+0x69/0xf0
> [ 86.929627][ T1] ? rethook_trampoline_handler+0x8e/0x200
> [ 86.929629][ T1] ? rethook_trampoline_handler+0x91/0x200
> [ 86.929631][ T1] arch_rethook_trampoline_callback+0x36/0x50
> [ 86.929635][ T1] arch_rethook_trampoline+0x2c/0x60
> [ 86.929639][ T1] ? ksys_read+0x69/0xf0
> [ 86.929640][ T1] osnoise_arch_unregister+0x210/0x210
> [ 86.929643][ T1] do_syscall_64+0x87/0x1b0
> [ 86.929645][ T1] entry_SYSCALL_64_after_hwframe+0x6e/0x76
> [ 86.929647][ T1] RIP: 0033:0x7f0ec49230ea
> [ 86.929653][ T1] Code: 55 48 89 e5 48 83 ec 20 48 89 55 e8 48 89 75 f0 89 7d f8 e8 e8 79 f8 ff 48 8b 55 e8 48 8b 75 f0 41 89 c0 8b 7d f8 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 2e 44 89 c7 48 89 45 f8 e8 42 7a f8 ff 48 8b
> [ 86.929655][ T1] RSP: 002b:00007ffead1dc7a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> [ 86.929656][ T1] RAX: ffffffffffffffda RBX: 00005625bff4efe0 RCX: 00007f0ec49230ea
> [ 86.929657][ T1] RDX: 0000000000000400 RSI: 00005625bfeda010 RDI: 0000000000000019
> [ 86.929658][ T1] RBP: 00007ffead1dc7c0 R08: 0000000000000000 R09: 0000000000000001
> [ 86.929659][ T1] R10: 0000000000001000 R11: 0000000000000246 R12: 00007f0ec49f3660
> [ 86.929659][ T1] R13: 00007f0ec50127d0 R14: 0000000000000a68 R15: 00007f0ec49f2d60
> [ 86.929663][ T1] </TASK>
> [ 86.929663][ T1] Modules linked in: intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
> [ 86.929676][ T1] ---[ end trace 0000000000000000 ]---
> [ 86.929677][ T1] RIP: 0010:rethook_trampoline_handler+0x8e/0x200
> [ 86.929679][ T1] Code: 5e 20 00 48 8b a8 c8 2a 00 00 48 85 ed 75 2f e9 8b 00 00 00 4d 85 ed 74 17 48 8b 45 08 48 8d 7d f0 4c 89 f9 4c 89 e2 48 8b 30 <41> ff d5 0f 1f 00 48 39 dd 74 6a 48 8b 6d 00 48 85 ed 74 61 4c 39
> [ 86.929680][ T1] RSP: 0018:ffffc90001e0bdf8 EFLAGS: 00010286
> [ 86.929681][ T1] RAX: ffffc90001e0bef0 RBX: ffff8881775999a0 RCX: ffffc90001e0be40
> [ 86.929682][ T1] RDX: ffffffff81545129 RSI: 0000000000000000 RDI: ffff888177599990
> [ 86.929683][ T1] RBP: ffff8881775999a0 R08: 0000000000000000 R09: ffff88810246af00
> [ 86.929684][ T1] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81545129
> [ 86.929685][ T1] R13: ef01a20a8bd21200 R14: ffffc90001e0bee8 R15: ffffc90001e0be40
> [ 86.929686][ T1] FS: 00007f0ec5012940(0000) GS:ffff88846d600000(0000) knlGS:0000000000000000
> [ 86.929687][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 86.929688][ T1] CR2: 00005595e83bf5b0 CR3: 000000010805e001 CR4: 0000000000770ef0
> [ 86.929688][ T1] PKRU: 55555554
> [ 86.929689][ T1] note: systemd[1] exited with preempt_count 1
> [ 86.929692][ T1] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> [ 86.929992][ T1] Kernel Offset: disabled
--
Masami Hiramatsu (Google) <[email protected]>
On Thu, 29 Feb 2024 14:51:39 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:
> On Wed, 28 Feb 2024 17:23:34 +0100
> Jiri Olsa <[email protected]> wrote:
>
> > On Mon, Feb 26, 2024 at 12:57:53PM +0900, Masami Hiramatsu (Google) wrote:
> > > Hi,
> > >
> > > Here is version 2 series of patches to support accessing function entry data
> > > from function *return* probes (including kretprobe and fprobe-exit event).
> > >
> > > In this version, I added another cleanup [4/7], updated README[5/7], added
> > > testcases[6/7] and updated document[7/7].
> > >
> > > This allows us to access the results of some functions, which returns the
> > > error code and its results are passed via function parameter, such as an
> > > structure-initialization function.
> > >
> > > For example, vfs_open() will link the file structure to the inode and update
> > > mode. Thus we can trace that changes.
> > >
> > > # echo 'f vfs_open mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
> > > # echo 'f vfs_open%return mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events
> > > # echo 1 > events/fprobes/enable
> > > # cat trace
> > > sh-131 [006] ...1. 1945.714346: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x2 inode=0x0
> > > sh-131 [006] ...1. 1945.714358: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4d801e inode=0xffff888008470168
> > > cat-143 [007] ...1. 1945.717949: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
> > > cat-143 [007] ...1. 1945.717956: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4a801d inode=0xffff888005f78d28
> > > cat-143 [007] ...1. 1945.720616: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0
> > > cat-143 [007] ...1. 1945.728263: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0xa800d inode=0xffff888004ada8d8
> >
> > hi,
> > I hit a crash while playing with this, by runnning:
> >
> > # echo 'f vfs_read%return $arg*' >> dynamic_events
> > # echo 1 > events/fprobes/enable
>
> Thanks for reporting! But I can not reproduce it.
> Can you share your kconfig?
No problem, I could reproduce it.
/sys/kernel/tracing # echo 'f vfs_read%return $arg* $retval' >> dynamic_events
/sys/kernel/tracing # echo 1 > events/fprobes/enable
/sys/kernel/tracing #
/sys/kernel/tracing # [ 67.709725] general protection fault, maybe for address 0xffffc9000047bef8: 0000 [#1] PREEMPT SMP PTI
[ 67.714672] CPU: 5 PID: 132 Comm: sh Tainted: G N 6.8.0-rc5-00007-gd5e41e4cee7e #149
[ 67.716491] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 67.718036] RIP: 0010:__x86_indirect_thunk_r13+0xa/0x20
[ 67.719087] Code: e8 01 00 00 00 cc 4c 89 24 24 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 0f 1f 44 00 00 e8 01 00 00 00 cc 4c 89 2c 24 <c3> cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 0f 1f 44 00 00
[ 67.722314] RSP: 0018:ffffc9000047bdf0 EFLAGS: 00010286
[ 67.723251] RAX: ffffc9000047bef8 RBX: ffff8880073258e0 RCX: ffffc9000047be48
[ 67.724704] RDX: ffffffff813aba09 RSI: 0000000000000000 RDI: ffff8880073258d0
[ 67.725840] RBP: ffff8880073258e0 R08: 0000000000000000 R09: ffff888005053648
[ 67.727017] R10: ffff888008452388 R11: 0000000000000001 R12: ffffffff813aba09
[ 67.728107] R13: 9c73d7ba3660c600 R14: ffffc9000047bef0 R15: ffffc9000047be48
[ 67.729630] FS: 000000000115d8c0(0000) GS:ffff88807d940000(0000) knlGS:0000000000000000
[ 67.731231] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 67.732285] CR2: 00000000005a2319 CR3: 0000000005ad6000 CR4: 00000000000006b0
[ 67.733502] Call Trace:
[ 67.734013] <TASK>
[ 67.734504] ? die_addr+0x37/0x90
[ 67.735307] ? exc_general_protection+0x1ac/0x3f0
[ 67.736158] ? asm_exc_general_protection+0x26/0x30
[ 67.736984] ? ksys_read+0x69/0xf0
[ 67.737559] ? ksys_read+0x69/0xf0
[ 67.738142] ? __x86_indirect_thunk_r13+0xa/0x20
[ 67.739160] ? rethook_trampoline_handler+0x95/0x200
[ 67.739919] ? arch_rethook_trampoline_callback+0x3a/0x50
[ 67.740665] ? arch_rethook_trampoline+0x2c/0x60
[ 67.741362] ? ksys_read+0x69/0xf0
[ 67.741980] ? trace_clock_x86_tsc+0x20/0x20
[ 67.742662] ? do_syscall_64+0xcc/0x1e0
[ 67.743289] ? entry_SYSCALL_64_after_hwframe+0x6f/0x77
[ 67.744620] </TASK>
[ 67.745044] Modules linked in:
[ 67.745559] ---[ end trace 0000000000000000 ]---
[ 67.746221] RIP: 0010:__x86_indirect_thunk_r13+0xa/0x20
[ 67.746927] Code: e8 01 00 00 00 cc 4c 89 24 24 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 0f 1f 44 00 00 e8 01 00 00 00 cc 4c 89 2c 24 <c3> cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 0f 1f 44 00 00
[ 67.749176] RSP: 0018:ffffc9000047bdf0 EFLAGS: 00010286
[ 67.749835] RAX: ffffc9000047bef8 RBX: ffff8880073258e0 RCX: ffffc9000047be48
[ 67.750687] RDX: ffffffff813aba09 RSI: 0000000000000000 RDI: ffff8880073258d0
[ 67.751880] RBP: ffff8880073258e0 R08: 0000000000000000 R09: ffff888005053648
[ 67.752810] R10: ffff888008452388 R11: 0000000000000001 R12: ffffffff813aba09
[ 67.753721] R13: 9c73d7ba3660c600 R14: ffffc9000047bef0 R15: ffffc9000047be48
[ 67.754554] FS: 000000000115d8c0(0000) GS:ffff88807d940000(0000) knlGS:0000000000000000
[ 67.755568] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 67.756278] CR2: 00000000005a2319 CR3: 0000000005ad6000 CR4: 00000000000006b0
[ 67.757089] Kernel panic - not syncing: Fatal exception
[ 67.757917] Kernel Offset: disabled
[ 67.758404] ---[ end Kernel panic - not syncing: Fatal exception ]---
Hmm, this seems arch_rethook_trampoline caused the issue.
And curiously, it depends on the number of stored data.
OK:
/sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3' >> dynamic_events
/sys/kernel/tracing # echo 1 > events/fprobes/enable
NG:
/sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3 $arg4' >> dynamic_events
/sys/kernel/tracing # echo 1 > events/fprobes/enable
I also confirmed that on 'vfs_write' caused the same result. 3 arguments(24 bytes) is OK,
but 4 arguments (32bytes) is NG.
Thank you,
--
Masami Hiramatsu (Google) <[email protected]>
On Thu, 29 Feb 2024 15:38:55 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:
> Hmm, this seems arch_rethook_trampoline caused the issue.
>
> And curiously, it depends on the number of stored data.
>
> OK:
> /sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3' >> dynamic_events
> /sys/kernel/tracing # echo 1 > events/fprobes/enable
>
> NG:
> /sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3 $arg4' >> dynamic_events
> /sys/kernel/tracing # echo 1 > events/fprobes/enable
>
> I also confirmed that on 'vfs_write' caused the same result. 3 arguments(24 bytes) is OK,
> but 4 arguments (32bytes) is NG.
And this may be the fprobe bug. kretprobe events doesn't show this issue.
OK:
/sys/kernel/tracing # echo 'r vfs_read $arg*' >> kprobe_events
/sys/kernel/tracing # echo 1 > events/kprobes/enable
But this is strange because both uses same rethook...
Thank you,
--
Masami Hiramatsu (Google) <[email protected]>
On Thu, 29 Feb 2024 16:13:20 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:
> On Thu, 29 Feb 2024 15:38:55 +0900
> Masami Hiramatsu (Google) <[email protected]> wrote:
>
> > Hmm, this seems arch_rethook_trampoline caused the issue.
> >
> > And curiously, it depends on the number of stored data.
> >
> > OK:
> > /sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3' >> dynamic_events
> > /sys/kernel/tracing # echo 1 > events/fprobes/enable
> >
> > NG:
> > /sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3 $arg4' >> dynamic_events
> > /sys/kernel/tracing # echo 1 > events/fprobes/enable
> >
> > I also confirmed that on 'vfs_write' caused the same result. 3 arguments(24 bytes) is OK,
> > but 4 arguments (32bytes) is NG.
>
> And this may be the fprobe bug. kretprobe events doesn't show this issue.
>
> OK:
> /sys/kernel/tracing # echo 'r vfs_read $arg*' >> kprobe_events
> /sys/kernel/tracing # echo 1 > events/kprobes/enable
>
> But this is strange because both uses same rethook...
Lol, I haven't allocate the entry data size when initialize rethook.
That's a bug.
Please try below.
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 6cd2a4e3afb8..9ff018245840 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -189,9 +189,6 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
{
int size;
- if (num <= 0)
- return -EINVAL;
-
if (!fp->exit_handler) {
fp->rethook = NULL;
return 0;
@@ -199,15 +196,16 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
/* Initialize rethook if needed */
if (fp->nr_maxactive)
- size = fp->nr_maxactive;
+ num = fp->nr_maxactive;
else
- size = num * num_possible_cpus() * 2;
- if (size <= 0)
+ num *= num_possible_cpus() * 2;
+ if (num <= 0)
return -EINVAL;
+ size = sizeof(struct fprobe_rethook_node) + fp->entry_data_size;
+
/* Initialize rethook */
- fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler,
- sizeof(struct fprobe_rethook_node), size);
+ fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, size, num);
if (IS_ERR(fp->rethook))
return PTR_ERR(fp->rethook);
--
Masami Hiramatsu (Google) <[email protected]>
On Thu, 29 Feb 2024 17:52:16 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:
> Lol, I haven't allocate the entry data size when initialize rethook.
> That's a bug.
> Please try below.
I'll wait to review patches 5,6,7 as I'm guessing this will have a v3?
-- Steve
On Thu, 29 Feb 2024 22:41:34 -0500
Steven Rostedt <[email protected]> wrote:
> On Thu, 29 Feb 2024 17:52:16 +0900
> Masami Hiramatsu (Google) <[email protected]> wrote:
>
> > Lol, I haven't allocate the entry data size when initialize rethook.
> > That's a bug.
> > Please try below.
>
> I'll wait to review patches 5,6,7 as I'm guessing this will have a v3?
Ah, actually I pushed this fix separately because it is an actual
bug and may silently cause an issue in the selftest. I pushed it
in probes-fixes-v6.8-rc5.
Anyway, let me send v3 it with that fix.
Thank you,
>
> -- Steve
>
--
Masami Hiramatsu (Google) <[email protected]>