From: Andreas Schwab <schwab@linux-m68k.org>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Szabolcs Nagy via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH v2 01/14] elf: Fix a DTV setup issue [BZ #27136]
Date: Tue, 13 Apr 2021 12:51:25 +0200 [thread overview]
Message-ID: <87blaih2z6.fsf@igel.home> (raw)
In-Reply-To: <20210413103450.GW23289@arm.com> (Szabolcs Nagy's message of "Tue, 13 Apr 2021 11:34:50 +0100")
On Apr 13 2021, Szabolcs Nagy wrote:
> The 04/13/2021 12:22, Andreas Schwab wrote:
>> On Apr 13 2021, Szabolcs Nagy wrote:
>>
>> > The 04/13/2021 10:36, Andreas Schwab wrote:
>> >> On Apr 13 2021, Szabolcs Nagy via Libc-alpha wrote:
>> >>
>> >> > The max modid is a valid index in the dtv, it should not be skipped.
>> >>
>> >> Does this check in _dl_allocate_tls_init need to be adjusted as well?
>> >>
>> >> /* Check if the current dtv is big enough. */
>> >> if (dtv[-1].counter < GL(dl_tls_max_dtv_idx))
>> >
>> > no, that seems fine because counter is not the dtv length but
>> > the maximum valid index (dtv[dtv[-1].counter] is valid, the
>> > dtv array size is counter+2 to accomodate for dtv[-1] and [0])
>>
>> Since both dtv[-1].counter and GL(dl_tls_max_dtv_idx) are indexes, not
>> lengths, I would expect them to be compared with <=.
>
> but the code is
>
> /* Check if the current dtv is big enough. */
> if (dtv[-1].counter < GL(dl_tls_max_dtv_idx))
> {
> /* Resize the dtv. */
> dtv = _dl_resize_dtv (dtv, GL(dl_tls_max_dtv_idx));
>
> in case of == there is no need to resize: the dtv array is
> large enough for the observed GL(dl_tls_max_dtv_idx).
I think it would be easier to understand if the condition would be
written as (GL(dl_tls_max_dtv_idx) > dtv[-1].counter).
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
next prev parent reply other threads:[~2021-04-13 10:51 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 8:17 [PATCH v2 00/14] Dynamic TLS related data race fixes Szabolcs Nagy
2021-04-13 8:18 ` [PATCH v2 01/14] elf: Fix a DTV setup issue [BZ #27136] Szabolcs Nagy
2021-04-13 8:36 ` Andreas Schwab
2021-04-13 9:35 ` Szabolcs Nagy
2021-04-13 10:22 ` Andreas Schwab
2021-04-13 10:34 ` Szabolcs Nagy
2021-04-13 10:51 ` Andreas Schwab [this message]
2021-04-13 8:18 ` [PATCH v2 02/14] elf: Add a DTV setup test " Szabolcs Nagy
2021-04-14 18:06 ` Adhemerval Zanella
2021-04-15 9:53 ` Szabolcs Nagy
2021-04-13 8:18 ` [PATCH v2 03/14] elf: Fix comments and logic in _dl_add_to_slotinfo Szabolcs Nagy
2021-04-14 18:12 ` Adhemerval Zanella
2021-04-13 8:18 ` [PATCH v2 04/14] elf: Refactor _dl_update_slotinfo to avoid use after free Szabolcs Nagy
2021-04-14 18:20 ` Adhemerval Zanella
2021-04-13 8:19 ` [PATCH v2 05/14] elf: Fix data races in pthread_create and TLS access [BZ #19329] Szabolcs Nagy
2021-04-15 17:44 ` Adhemerval Zanella
2021-04-13 8:19 ` [PATCH v2 06/14] elf: Use relaxed atomics for racy accesses " Szabolcs Nagy
2021-04-15 18:21 ` Adhemerval Zanella
2021-04-16 9:12 ` Szabolcs Nagy
2021-05-11 2:56 ` Carlos O'Donell
2021-05-11 9:31 ` Szabolcs Nagy
2021-05-11 16:19 ` Szabolcs Nagy
2021-05-12 20:33 ` Carlos O'Donell
2021-04-13 8:19 ` [PATCH v2 07/14] elf: Add test case for " Szabolcs Nagy
2021-04-15 19:21 ` Adhemerval Zanella
2021-04-13 8:20 ` [PATCH v2 08/14] elf: Fix DTV gap reuse logic [BZ #27135] Szabolcs Nagy
2021-04-15 19:45 ` Adhemerval Zanella
2021-06-24 9:48 ` Florian Weimer
2021-06-24 12:27 ` Florian Weimer
2021-06-24 12:57 ` Adhemerval Zanella
2021-06-24 14:20 ` Florian Weimer
2021-06-24 18:58 ` Szabolcs Nagy
2021-04-13 8:20 ` [PATCH v2 09/14] x86_64: Avoid lazy relocation of tlsdesc [BZ #27137] Szabolcs Nagy
2021-04-13 14:02 ` H.J. Lu
2021-04-13 8:20 ` [PATCH v2 10/14] i386: " Szabolcs Nagy
2021-04-13 14:02 ` H.J. Lu
2021-04-13 8:21 ` [PATCH v2 11/14] x86_64: Remove lazy tlsdesc relocation related code Szabolcs Nagy
2021-04-13 14:03 ` H.J. Lu
2021-04-13 8:21 ` [PATCH v2 12/14] i386: " Szabolcs Nagy
2021-04-13 14:04 ` H.J. Lu
2021-04-13 8:21 ` [PATCH v2 13/14] elf: " Szabolcs Nagy
2021-04-15 19:52 ` Adhemerval Zanella
2021-04-13 8:21 ` [PATCH v2 14/14] RFC elf: Fix slow tls access after dlopen [BZ #19924] Szabolcs Nagy
2022-09-16 9:54 ` Carlos O'Donell
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