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BAYES_HAM(-3.00)[99.99%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.de:mid]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[gdb-patches@sourceware.org]; RCVD_TLS_ALL(0.00)[] X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces~public-inbox=simark.ca@sourceware.org I wrote a patch containing: ... dw2_instantiate_symtab (cu->per_cu, ...); ... and ran into a use-after-free at a following use of cu. The problem is that dw2_instantiate_symtab contains: ... free_cached_comp_units freer (per_objfile); ... and that the destructor does: ... ~free_cached_comp_units () { m_per_objfile->remove_all_cus (); } ... which also frees the cu we used in the cu->per_cu argument to dw2_instantiate_symtab. Detect this situation using an assert in the free_cached_comp_units constructor. Tested on aarch64-linux. --- gdb/dwarf2/read.c | 3 +++ gdb/dwarf2/read.h | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index c761b732819..0dd0e944597 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -902,6 +902,9 @@ class free_cached_comp_units explicit free_cached_comp_units (dwarf2_per_objfile *per_objfile) : m_per_objfile (per_objfile) { + /* The destructor frees all cached comp units, including ones currently + cached, so check that there are no currently cached comp units. */ + gdb_assert (m_per_objfile->nr_of_cus () == 0); } ~free_cached_comp_units () diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h index 15dd2abf3a1..603fe089d6a 100644 --- a/gdb/dwarf2/read.h +++ b/gdb/dwarf2/read.h @@ -969,6 +969,12 @@ struct dwarf2_per_objfile /* Free all cached compilation units. */ void remove_all_cus (); + /* Return the number of cached compilation units. */ + size_t nr_of_cus () const + { + return m_dwarf2_cus.size (); + } + /* Increase the age counter on each CU compilation unit and free any that are too old. */ void age_comp_units (); base-commit: a8740b7533b4df34d4d7bc5be9bb2108d019fce5 -- 2.51.0