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Message-ID: <ZL51o59_yYS_3Yal@alley>
Date: Mon, 24 Jul 2023 14:59:15 +0200
From: Petr Mladek <pmladek@...e.com>
To: Rong Tao <rtoax@...mail.com>, Luis Chamberlain <mcgrof@...nel.org>
Cc: prasad@...ux.vnet.ibm.com, ast@...nel.org, frederic@...nel.org,
gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
mbenes@...e.cz, qperret@...gle.com, rongtao@...tc.cn,
tglx@...utronix.de, will@...nel.org, mhiramat@...nel.org
Subject: Re: [PATCH] samples/hw_breakpoint: Fix kernel BUG 'invalid opcode:
0000'
On Mon 2023-07-24 18:47:58, Rong Tao wrote:
> From: Rong Tao <rongtao@...tc.cn>
>
> Macro symbol_put() is defined as __symbol_put(__stringify(x))
>
> ksym_name = "jiffies"
> symbol_put(ksym_name)
>
> will be resolved as
>
> __symbol_put("ksym_name")
>
> which is clearly wrong. So symbol_put must be replaced with __symbol_put.
>
> When we uninstall hw_breakpoint.ko (rmmod), a kernel bug occurs with the
> following error:
>
> [11381.854152] kernel BUG at kernel/module/main.c:779!
> [11381.854159] invalid opcode: 0000 [#2] PREEMPT SMP PTI
> [11381.854163] CPU: 8 PID: 59623 Comm: rmmod Tainted: G D OE 6.2.9-200.fc37.x86_64 #1
> [11381.854167] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./B360M-HDV, BIOS P3.20 10/23/2018
> [11381.854169] RIP: 0010:__symbol_put+0xa2/0xb0
> [11381.854175] Code: 00 e8 92 d2 f7 ff 65 8b 05 c3 2f e6 78 85 c0 74 1b 48 8b 44 24 30 65 48 2b 04 25 28 00 00 00 75 12 48 83 c4 38 c3 cc cc cc cc <0f> 0b 0f 1f 44 00 00 eb de e8 c0 df d8 00 90 90 90 90 90 90 90 90
> [11381.854178] RSP: 0018:ffffad8ec6ae7dd0 EFLAGS: 00010246
> [11381.854181] RAX: 0000000000000000 RBX: ffffffffc1fd1240 RCX: 000000000000000c
> [11381.854184] RDX: 000000000000006b RSI: ffffffffc02bf7c7 RDI: ffffffffc1fd001c
> [11381.854186] RBP: 000055a38b76e7c8 R08: ffffffff871ccfe0 R09: 0000000000000000
> [11381.854188] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> [11381.854190] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [11381.854192] FS: 00007fbf7c62c740(0000) GS:ffff8c5badc00000(0000) knlGS:0000000000000000
> [11381.854195] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [11381.854197] CR2: 000055a38b7793f8 CR3: 0000000363e1e001 CR4: 00000000003726e0
> [11381.854200] DR0: ffffffffb3407980 DR1: 0000000000000000 DR2: 0000000000000000
> [11381.854202] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [11381.854204] Call Trace:
> [11381.854207] <TASK>
> [11381.854212] s_module_exit+0xc/0xff0 [symbol_getput]
> [11381.854219] __do_sys_delete_module.constprop.0+0x198/0x2f0
> [11381.854225] do_syscall_64+0x58/0x80
> [11381.854231] ? exit_to_user_mode_prepare+0x180/0x1f0
> [11381.854237] ? syscall_exit_to_user_mode+0x17/0x40
> [11381.854241] ? do_syscall_64+0x67/0x80
> [11381.854245] ? syscall_exit_to_user_mode+0x17/0x40
> [11381.854248] ? do_syscall_64+0x67/0x80
> [11381.854252] ? exc_page_fault+0x70/0x170
> [11381.854256] entry_SYSCALL_64_after_hwframe+0x72/0xdc
>
> Signed-off-by: Rong Tao <rongtao@...tc.cn>
Reviewed-by: Petr Mladek <pmladek@...e.com>
I have already seen and acked this patch few months ago, see
https://lore.kernel.org/all/ZD0TfQHWQftNvFNA@alley/#t
symbol_put() is in module loader code, so this might go via
the module loaded tree. Adding Luis into Cc.
Best Regards,
Petr
---
> samples/hw_breakpoint/data_breakpoint.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c
> index 418c46fe5ffc..9debd128b2ab 100644
> --- a/samples/hw_breakpoint/data_breakpoint.c
> +++ b/samples/hw_breakpoint/data_breakpoint.c
> @@ -70,7 +70,7 @@ static int __init hw_break_module_init(void)
> static void __exit hw_break_module_exit(void)
> {
> unregister_wide_hw_breakpoint(sample_hbp);
> - symbol_put(ksym_name);
> + __symbol_put(ksym_name);
> printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name);
> }
>
> --
> 2.39.3
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