From: Pedro Alves <pedro@palves.net>
To: Thiago Jung Bauermann <thiago.bauermann@linaro.org>,
gdb-patches@sourceware.org
Cc: Simon Marchi <simon.marchi@efficios.com>
Subject: Re: [PATCH v3 2/8] gdbserver: Add PID parameter to linux_get_auxv and linux_get_hwcap
Date: Mon, 6 Feb 2023 19:54:19 +0000 [thread overview]
Message-ID: <ed619f17-b966-514e-5fc9-3732934d9e15@palves.net> (raw)
In-Reply-To: <20230130044518.3322695-3-thiago.bauermann@linaro.org>
On 2023-01-30 4:45 a.m., Thiago Jung Bauermann via Gdb-patches wrote:
> This patch doesn't change gdbserver behaviour,
That's not actually true -- before the patch, we use the lwpid
of the current thread, while after the patch we always use the pid of the
process.
Here:
> int
> -linux_process_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
> - unsigned int len)
> +linux_process_target::read_auxv (int pid, CORE_ADDR offset,
> + unsigned char *myaddr, unsigned int len)
> {
> char filename[PATH_MAX];
> int fd, n;
> - int pid = lwpid_of (current_thread);
>
> xsnprintf (filename, sizeof filename, "/proc/%d/auxv", pid);
>
AFAICT by playing with debugging the gdb.threads/leader-exit.exp program,
you can't read /proc/PID/auxv if the leader thread has exited (is zombie).
Maybe that ends up not mattering in practice, not sure, but it is a
behavior change.
> but after later changes are
> made it avoids a null pointer dereference when HWCAP needs to be obtained
> for a specific process while current_thread is nullptr.
>
> Fixing linux_read_auxv, linux_get_hwcap and linux_get_hwcap2 to take a PID
> parameter seems more correct than setting current_thread in one particular
> code path.
>
> Changes are propagated to allow passing the new parameter through the call
> chain.
>
> Approved-By: Simon Marchi <simon.marchi@efficios.com>
> ---
> gdbserver/linux-aarch64-low.cc | 7 ++++---
> gdbserver/linux-arm-low.cc | 2 +-
> gdbserver/linux-low.cc | 18 +++++++++---------
> gdbserver/linux-low.h | 9 ++++-----
> gdbserver/linux-ppc-low.cc | 6 +++---
> gdbserver/linux-s390-low.cc | 2 +-
> gdbserver/netbsd-low.cc | 4 +---
> gdbserver/netbsd-low.h | 2 +-
> gdbserver/server.cc | 3 ++-
> gdbserver/target.cc | 4 ++--
> gdbserver/target.h | 4 ++--
> 11 files changed, 30 insertions(+), 31 deletions(-)
>
> diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
> index 3c09e086afee..2ed6e95562c5 100644
> --- a/gdbserver/linux-aarch64-low.cc
> +++ b/gdbserver/linux-aarch64-low.cc
> @@ -846,12 +846,13 @@ aarch64_target::low_arch_setup ()
> if (is_elf64)
> {
> struct aarch64_features features;
> + int pid = current_thread->id.pid ();
You can also write:
current_process ()->pid
which is a more to the point. Also, sometimes there's a current
process, but not a current thread, so when we don't actually need a thread,
current_process() is better.
Pedro Alves
next prev parent reply other threads:[~2023-02-06 19:54 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-30 4:45 [PATCH v3 0/8] gdbserver improvements for AArch64 SVE support Thiago Jung Bauermann
2023-01-30 4:45 ` [PATCH v3 1/8] gdbserver: Add assert in find_register_by_number Thiago Jung Bauermann
2023-01-31 17:05 ` Simon Marchi
2023-01-31 19:49 ` Thiago Jung Bauermann
2023-02-01 15:43 ` Simon Marchi
2023-01-30 4:45 ` [PATCH v3 2/8] gdbserver: Add PID parameter to linux_get_auxv and linux_get_hwcap Thiago Jung Bauermann
2023-02-01 9:07 ` Luis Machado
2023-02-01 10:54 ` Andrew Burgess
2023-02-01 16:01 ` Simon Marchi
2023-02-01 19:33 ` Thiago Jung Bauermann
2023-02-01 19:53 ` Simon Marchi
2023-02-01 21:55 ` Thiago Jung Bauermann
2023-02-06 19:54 ` Pedro Alves [this message]
2023-02-06 20:16 ` Simon Marchi
2023-02-07 15:19 ` Pedro Alves
2023-02-07 21:47 ` Thiago Jung Bauermann
2023-02-09 1:31 ` Simon Marchi
2023-02-10 3:54 ` Thiago Jung Bauermann
2023-02-07 22:28 ` Thiago Jung Bauermann
2023-01-30 4:45 ` [PATCH v3 3/8] gdbserver/linux-aarch64: Factor out function to get aarch64_features Thiago Jung Bauermann
2023-02-01 8:59 ` Luis Machado
2023-02-01 16:04 ` Simon Marchi
2023-02-01 22:13 ` Thiago Jung Bauermann
2023-01-30 4:45 ` [PATCH v3 4/8] gdbserver/linux-aarch64: When thread stops, update its target description Thiago Jung Bauermann
2023-02-01 9:05 ` Luis Machado
2023-02-01 11:06 ` Andrew Burgess
2023-02-01 16:21 ` Simon Marchi
2023-02-01 16:32 ` Luis Machado
2023-02-02 2:54 ` Thiago Jung Bauermann
2023-02-02 3:47 ` Simon Marchi
2023-02-03 3:47 ` Thiago Jung Bauermann
2023-02-03 11:13 ` Luis Machado
2023-02-04 15:26 ` Thiago Jung Bauermann
2023-02-03 11:11 ` Luis Machado
2023-02-04 15:21 ` Thiago Jung Bauermann
2023-02-06 9:07 ` Luis Machado
2023-02-06 12:15 ` Thiago Jung Bauermann
2023-02-06 20:29 ` Pedro Alves
2023-02-07 8:11 ` Luis Machado
2023-02-07 14:39 ` Thiago Jung Bauermann
2023-02-03 10:57 ` Luis Machado
2023-02-04 6:18 ` Thiago Jung Bauermann
2023-02-06 20:26 ` Pedro Alves
2023-02-07 21:06 ` Thiago Jung Bauermann
2023-02-09 2:46 ` Simon Marchi
2023-02-10 3:29 ` Thiago Jung Bauermann
2023-02-10 14:56 ` Luis Machado
2023-02-10 15:04 ` Tom Tromey
2023-02-10 15:28 ` Luis Machado
2023-02-10 17:26 ` Thiago Jung Bauermann
2023-02-10 21:01 ` Simon Marchi
2023-01-30 4:45 ` [PATCH v3 5/8] gdbserver: Transmit target description ID in thread list and stop reply Thiago Jung Bauermann
2023-01-30 12:52 ` Eli Zaretskii
2023-01-30 14:05 ` Thiago Jung Bauermann
2023-02-01 9:39 ` Luis Machado
2023-02-01 12:07 ` Andrew Burgess
2023-02-01 13:03 ` Eli Zaretskii
2023-02-01 17:37 ` Simon Marchi
2023-02-02 20:36 ` Thiago Jung Bauermann
2023-02-02 20:56 ` Simon Marchi
2023-02-01 20:46 ` Simon Marchi
2023-02-02 21:43 ` Thiago Jung Bauermann
2023-02-01 14:51 ` Andrew Burgess
2023-02-01 17:03 ` Simon Marchi
2023-02-02 19:52 ` Thiago Jung Bauermann
2023-02-02 20:51 ` Simon Marchi
2023-02-03 2:44 ` Thiago Jung Bauermann
2023-02-03 16:29 ` Andrew Burgess
2023-02-04 6:08 ` Thiago Jung Bauermann
2023-02-03 11:22 ` Luis Machado
2023-02-03 12:50 ` Simon Marchi
2023-01-30 4:45 ` [PATCH v3 6/8] gdb/remote: Parse tdesc field in stop reply and threads list XML Thiago Jung Bauermann
2023-02-01 9:52 ` Luis Machado
2023-02-05 0:06 ` Thiago Jung Bauermann
2023-02-06 9:10 ` Luis Machado
2023-02-01 14:32 ` Andrew Burgess
2023-02-01 19:50 ` Simon Marchi
2023-02-01 20:16 ` Simon Marchi
2023-02-03 11:27 ` Luis Machado
2023-02-03 13:19 ` Simon Marchi
2023-02-03 16:33 ` Andrew Burgess
2023-01-30 4:45 ` [PATCH v3 7/8] gdb/aarch64: Detect vector length changes when debugging remotely Thiago Jung Bauermann
2023-02-01 9:58 ` Luis Machado
2023-02-01 15:26 ` Andrew Burgess
2023-02-01 20:20 ` Simon Marchi
2023-02-03 11:31 ` Luis Machado
2023-02-03 16:38 ` Andrew Burgess
2023-02-03 19:07 ` Simon Marchi
2023-01-30 4:45 ` [PATCH v3 8/8] gdb/testsuite: Add test to exercise multi-threaded AArch64 SVE inferiors Thiago Jung Bauermann
2023-02-01 10:10 ` Luis Machado
2023-02-06 19:11 ` [PATCH v3 0/8] gdbserver improvements for AArch64 SVE support Pedro Alves
2023-02-06 20:05 ` Simon Marchi
2023-02-06 21:06 ` Pedro Alves
2023-02-07 13:49 ` Simon Marchi
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