Control: tags -1 confirmed moreinfo On 2023-05-02 20:59:26 +0200, Salvatore Bonaccorso wrote: > Package: release.debian.org > Severity: normal > User: release.debian....@packages.debian.org > Usertags: unblock > X-Debbugs-Cc: dwar...@packages.debian.org, Aurelien Jarno > <aure...@debian.org>, k...@debian.org, vagr...@debian.org, Domenico Andreoli > <ca...@debian.org>, car...@debian.org > Control: affects -1 + src:dwarves > > Dear release team, > > Please unblock package dwarves > > [ Reason ] > Back in #1033301, Aurelien reported that the arm64 kernel size did > increase significantly due to issues with BTF deduplication. First > suspected to be a Linux kernel upstream issue, Aurelien discussed this > on with upstream and it was found that the issue is caused by a > src:dwarves regression (applied in 1.24-4). > > Details in https://bugs.debian.org/1033301#31 > > The (not yet uploaded) dwarves upload with attache debdiff > cherry-picks the upstream commit.
Please go ahead and remove the moreinfo tag once the package is available in unstable. Cheers > > (Please provide enough (but not too much) information to help > the release team to judge the request efficiently. E.g. by > filling in the sections below.) > > [ Impact ] > Increased arm64 kernel size. > > [ Tests ] > Apart from the report from Aurelien[1], package passes its autopkgtest. > > [1] https://lore.kernel.org/linux-arm-kernel/zezhajup21ln5...@aurel32.net/ > [ Risks ] > The upstream commit zero-initializes memory which previous was not > initialized after allocation, and might have contained garbage values > which were used. The fix is isolated as a oneliner. > > [ Checklist ] > [x] all changes are documented in the d/changelog > [x] I reviewed all changes and I approve them > [x] attach debdiff against the package in testing > > [ Other info ] > Ideally this enters the archive before a next upload for src:linux is > built (and which would be aimed for bookworm). > > unblock dwarves/1.24-4.1 > > Regards, > Salvatore > diff -Nru dwarves-1.24/debian/changelog dwarves-1.24/debian/changelog > --- dwarves-1.24/debian/changelog 2022-12-10 10:11:28.000000000 +0100 > +++ dwarves-1.24/debian/changelog 2023-05-02 20:37:16.000000000 +0200 > @@ -1,3 +1,13 @@ > +dwarves (1.24-4.1) unstable; urgency=medium > + > + * Non-maintainer upload. > + * dwarves: Zero-initialize struct cu in cu__new() to prevent incorrect BTF > + types. > + Fixes BTF deduplication issues causing arm64 kernel size increase. > + Thanks to Aurelien Jarno (Closes: #1033301) > + > + -- Salvatore Bonaccorso <car...@debian.org> Tue, 02 May 2023 20:37:16 +0200 > + > dwarves (1.24-4) unstable; urgency=medium > > * Backport upstream patches to support newer toolchains. > diff -Nru > dwarves-1.24/debian/patches/03-dwarves-Zero-initialize-struct-cu-in-cu__new-to-prev.patch > > dwarves-1.24/debian/patches/03-dwarves-Zero-initialize-struct-cu-in-cu__new-to-prev.patch > --- > dwarves-1.24/debian/patches/03-dwarves-Zero-initialize-struct-cu-in-cu__new-to-prev.patch > 1970-01-01 01:00:00.000000000 +0100 > +++ > dwarves-1.24/debian/patches/03-dwarves-Zero-initialize-struct-cu-in-cu__new-to-prev.patch > 2023-05-02 20:37:16.000000000 +0200 > @@ -0,0 +1,94 @@ > +From: Alan Maguire <alan.magu...@oracle.com> > +Date: Fri, 21 Oct 2022 16:02:03 +0100 > +Subject: dwarves: Zero-initialize struct cu in cu__new() to prevent incorrect > + BTF types > +Origin: > https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit?id=b72f5188856df0abf45e1a707856bb4e4e86153c > +Bug-Debian: https://bugs.debian.org/1033301 > + > +BTF deduplication was throwing some strange results, where core kernel > +data types were failing to deduplicate due to the return values > +of function type members being void (0) instead of the actual type > +(unsigned int). An example of this can be seen below, where > +"struct dst_ops" was failing to deduplicate between kernel and > +module: > + > +struct dst_ops { > + short unsigned int family; > + unsigned int gc_thresh; > + int (*gc)(struct dst_ops *); > + struct dst_entry * (*check)(struct dst_entry *, __u32); > + unsigned int (*default_advmss)(const struct dst_entry *); > + unsigned int (*mtu)(const struct dst_entry *); > +... > + > +struct dst_ops___2 { > + short unsigned int family; > + unsigned int gc_thresh; > + int (*gc)(struct dst_ops___2 *); > + struct dst_entry___2 * (*check)(struct dst_entry___2 *, __u32); > + void (*default_advmss)(const struct dst_entry___2 *); > + void (*mtu)(const struct dst_entry___2 *); > +... > + > +This was seen with > + > +bcc648a10cbc ("btf_encoder: Encode DW_TAG_unspecified_type returning > routines as void") > + > +...which rewrites the return value as 0 (void) when it is marked > +as matching DW_TAG_unspecified_type: > + > +static int32_t btf_encoder__tag_type(struct btf_encoder *encoder, uint32_t > type_id_off, uint32_t tag_type) > +{ > + if (tag_type == 0) > + return 0; > + > + if (encoder->cu->unspecified_type.tag && tag_type == > encoder->cu->unspecified_type.type) { > + // No provision for encoding this, turn it into void. > + return 0; > + } > + > + return type_id_off + tag_type; > +} > + > +However the odd thing was that on further examination, the unspecified type > +was not being set, so why was this logic being tripped? Futher debugging > +showed that the encoder->cu->unspecified_type.tag value was garbage, and > +the type id happened to collide with "unsigned int"; as a result we > +were replacing unsigned ints with void return values, and since this > +was being done to function type members in structs, it triggered a > +type mismatch which failed deduplication between kernel and module. > + > +The fix is simply to calloc() the cu in cu__new() instead. > + > +Committer notes: > + > +We have zalloc(size) as an alias to calloc(1, size), use it instead. > + > +Fixes: bcc648a10cbcd0b9 ("btf_encoder: Encode DW_TAG_unspecified_type > returning routines as void") > +Signed-off-by: Alan Maguire <alan.magu...@oracle.com> > +Acked-by: Andrii Nakryiko <and...@kernel.org> > +Acked-by: Jiri Olsa <jo...@kernel.org> > +Cc: b...@vger.kernel.org > +Cc: dwar...@vger.kernel.org > +Link: > https://lore.kernel.org/r/1666364523-9648-1-git-send-email-alan.magu...@oracle.com > +Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> > +--- > + dwarves.c | 2 +- > + 1 file changed, 1 insertion(+), 1 deletion(-) > + > +diff --git a/dwarves.c b/dwarves.c > +index fbebc1dda501..95a3bac0e36f 100644 > +--- a/dwarves.c > ++++ b/dwarves.c > +@@ -626,7 +626,7 @@ struct cu *cu__new(const char *name, uint8_t addr_size, > + const unsigned char *build_id, int build_id_len, > + const char *filename, bool use_obstack) > + { > +- struct cu *cu = malloc(sizeof(*cu) + build_id_len); > ++ struct cu *cu = zalloc(sizeof(*cu) + build_id_len); > + > + if (cu != NULL) { > + uint32_t void_id; > +-- > +2.40.1 > + > diff -Nru dwarves-1.24/debian/patches/series > dwarves-1.24/debian/patches/series > --- dwarves-1.24/debian/patches/series 2022-12-10 10:11:28.000000000 > +0100 > +++ dwarves-1.24/debian/patches/series 2023-05-02 20:37:16.000000000 > +0200 > @@ -1,3 +1,4 @@ > 00-store-the-CU-being-processed-to-avoid-changing-many-functions.patch > 01-record-if-a-CU-has-a-DW_TAG_unspecified_type.patch > 02-encode-DW_TAG_unspecified_type-returning-routines-as-void.patch > +03-dwarves-Zero-initialize-struct-cu-in-cu__new-to-prev.patch -- Sebastian Ramacher
