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erts: Fix crash in binary_to_term #11425

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Merged
sverker merged 1 commit into from
Aug 12, 2026
Merged

erts: Fix crash in binary_to_term #11425

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25 changes: 20 additions & 5 deletions erts/emulator/beam/external.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2026,11 +2026,25 @@ static BIF_RETTYPE binary_to_term_int(Process* p, Eterm bin, B2TContext *ctx)
break;

case B2TDecodeInit:
if (is_non_value(ctx->trap_bin) && ctx->b2ts.extsize > ctx->reds) {
/* dec_term will maybe trap, allocate space for magic bin
before result term to make it easy to trim with HRelease.
*/
ctx = b2t_export_context(p, ctx);
if (is_non_value(ctx->trap_bin)) {
if (ctx->b2ts.extsize > ctx->reds) {
/* dec_term will maybe trap, allocate space for magic bin
* before result term to make it easy to trim with HRelease.
*/
ctx = b2t_export_context(p, ctx);
}
else {
/*
* We will probably not trap. To ensure we don't,
* artificially increase our available reductions.
* This is a workaround for GH-11404. Calling HAlloc()
* in b2t_export_context() after factory has been created
* causes problems.
*/
const SWord consumed = initial_reds - ctx->reds;
ctx->reds = (INT_MAX / B2T_MEMCPY_FACTOR);
initial_reds = ctx->reds + consumed;
}
}
ctx->u.dc.ep = ctx->b2ts.extp;
ctx->u.dc.res = (Eterm) (UWord) NULL;
Expand Down Expand Up @@ -2114,6 +2128,7 @@ static BIF_RETTYPE binary_to_term_int(Process* p, Eterm bin, B2TContext *ctx)
}while (ctx->reds > 0 || ctx->state >= B2TDone);

if (is_non_value(ctx->trap_bin)) {
ASSERT(ctx->state < B2TDecode);
ctx = b2t_export_context(p, ctx);
ASSERT(is_value(ctx->trap_bin));
}
Expand Down
19 changes: 19 additions & 0 deletions erts/emulator/test/binary_SUITE.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,7 @@
bad_binary_to_term_2/1,safe_binary_to_term2/1,
bad_binary_to_term/1, bad_terms/1, more_bad_terms/1,
big_binary_to_term/1,
binary_to_term_trap_crash/1,
otp_5484/1,otp_5933/1,
ordering/1,unaligned_order/1,gc_test/1,
bit_sized_binary_sizes/1,
Expand Down Expand Up @@ -99,6 +100,7 @@ all() ->
bad_binary_to_term_2, safe_binary_to_term2,
bad_binary_to_term, bad_terms, t_hash, bad_size,
big_binary_to_term,
binary_to_term_trap_crash,
sub_bin_copy, bad_term_to_binary, t2b_system_limit,
term_to_iovec, more_bad_terms,
unsorted_map_in_map,
Expand Down Expand Up @@ -1951,6 +1953,23 @@ trapping_loop2(Bif,Args,N) ->
apply(erlang,Bif,Args),
trapping_loop2(Bif, Args, N-1).

%% GH-11404: Bug caused SEGV or failed ASSERT.
binary_to_term_trap_crash(Config) ->
Term = {0,"1234567890123456",0,0,0,0,0,0,
[1 bsl 47], [], {127,0,0,1},
0,[],[],[],[],[],[],[],[],[],[],0,[],"123456789",[],[],0,0,
0,[],0,[],[],[],[],[],1,[],[],[],[],[],[],0,0,"123",[],0,[],
1,[],[],[],0,0,{0,0},0,[],0,0,0,[],[],0,[],0,0,[]},
Bin = term_to_binary(Term),
CONTEXT_REDS = erlang:system_info(context_reductions),
[begin
erlang:yield(),
erlang:bump_reductions(I),
binary_to_term(Bin)
end
|| I <- lists:seq(1,CONTEXT_REDS)],
ok.

large(Config) when is_list(Config) ->
List = lists:flatten(lists:map(fun (_) ->
[0,1,2,3,4,5,6,7,8]
Expand Down
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