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author | Peter Zijlstra <peterz@infradead.org> | 2021-06-28 13:24:10 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-20 16:02:27 +0200 |
commit | a37c6588370eaf9aa9302a7b39b9035c06e89f78 (patch) | |
tree | 16096b7edbf4f121461b46527ee8c135aade6200 | |
parent | 1ff871b8ef77a233e79a3612fe943a6d3c8aff01 (diff) | |
download | linux-stable-a37c6588370eaf9aa9302a7b39b9035c06e89f78.tar.gz linux-stable-a37c6588370eaf9aa9302a7b39b9035c06e89f78.tar.bz2 linux-stable-a37c6588370eaf9aa9302a7b39b9035c06e89f78.zip |
jump_label: Fix jump_label_text_reserved() vs __init
[ Upstream commit 9e667624c291753b8a5128f620f493d0b5226063 ]
It turns out that jump_label_text_reserved() was reporting __init text
as being reserved past the time when the __init text was freed and
re-used.
For a long time, this resulted in, at worst, not being able to kprobe
text that happened to land at the re-used address. However a recent
commit e7bf1ba97afd ("jump_label, x86: Emit short JMP") made it a
fatal mistake because it now needs to read the instruction in order to
determine the conflict -- an instruction that's no longer there.
Fixes: 4c3ef6d79328 ("jump label: Add jump_label_text_reserved() to reserve jump points")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20210628113045.045141693@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r-- | kernel/jump_label.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/kernel/jump_label.c b/kernel/jump_label.c index ba39fbb1f8e7..af520ca26360 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -316,14 +316,16 @@ static int addr_conflict(struct jump_entry *entry, void *start, void *end) } static int __jump_label_text_reserved(struct jump_entry *iter_start, - struct jump_entry *iter_stop, void *start, void *end) + struct jump_entry *iter_stop, void *start, void *end, bool init) { struct jump_entry *iter; iter = iter_start; while (iter < iter_stop) { - if (addr_conflict(iter, start, end)) - return 1; + if (init || !jump_entry_is_init(iter)) { + if (addr_conflict(iter, start, end)) + return 1; + } iter++; } @@ -561,7 +563,7 @@ static int __jump_label_mod_text_reserved(void *start, void *end) ret = __jump_label_text_reserved(mod->jump_entries, mod->jump_entries + mod->num_jump_entries, - start, end); + start, end, mod->state == MODULE_STATE_COMING); module_put(mod); @@ -786,8 +788,9 @@ early_initcall(jump_label_init_module); */ int jump_label_text_reserved(void *start, void *end) { + bool init = system_state < SYSTEM_RUNNING; int ret = __jump_label_text_reserved(__start___jump_table, - __stop___jump_table, start, end); + __stop___jump_table, start, end, init); if (ret) return ret; |