6.11-stable review patch. If anyone has any objections, please let me know.
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From: Carlos Llamas cmllamas@google.com
[ Upstream commit 56ac7bd2c58a4e93d19f0ccb181035d075b315d3 ]
This reverts commit c02904f05ff805d6c0631634d5751ebd338f75ec.
Such commit assumed that only two symbols are relevant for the symbol size calculation. However, this can lead to an incorrect symbol size calculation when there are mapping symbols emitted by readelf.
For instance, when feeding 'update_irq_load_avg+0x1c/0x1c4', faddr2line might need to process the following readelf lines:
784284: ffffffc0081cca30 428 FUNC GLOBAL DEFAULT 2 update_irq_load_avg 87319: ffffffc0081ccb0c 0 NOTYPE LOCAL DEFAULT 2 $x.62522 87321: ffffffc0081ccbdc 0 NOTYPE LOCAL DEFAULT 2 $x.62524 87323: ffffffc0081ccbe0 0 NOTYPE LOCAL DEFAULT 2 $x.62526 87325: ffffffc0081ccbe4 0 NOTYPE LOCAL DEFAULT 2 $x.62528 87327: ffffffc0081ccbe8 0 NOTYPE LOCAL DEFAULT 2 $x.62530 87329: ffffffc0081ccbec 0 NOTYPE LOCAL DEFAULT 2 $x.62532 87331: ffffffc0081ccbf0 0 NOTYPE LOCAL DEFAULT 2 $x.62534 87332: ffffffc0081ccbf4 0 NOTYPE LOCAL DEFAULT 2 $x.62535 783403: ffffffc0081ccbf4 424 FUNC GLOBAL DEFAULT 2 sched_pelt_multiplier
The symbol size of 'update_irq_load_avg' should be calculated with the address of 'sched_pelt_multiplier', after skipping the mapping symbols seen in between. However, the offending commit cuts the list short and faddr2line incorrectly assumes 'update_irq_load_avg' is the last symbol in the section, resulting in:
$ scripts/faddr2line vmlinux update_irq_load_avg+0x1c/0x1c4 skipping update_irq_load_avg address at 0xffffffc0081cca4c due to size mismatch (0x1c4 != 0x3ff9a59988) no match for update_irq_load_avg+0x1c/0x1c4
After reverting the commit the issue is resolved:
$ scripts/faddr2line vmlinux update_irq_load_avg+0x1c/0x1c4 update_irq_load_avg+0x1c/0x1c4: cpu_of at kernel/sched/sched.h:1109 (inlined by) update_irq_load_avg at kernel/sched/pelt.c:481
Fixes: c02904f05ff8 ("scripts/faddr2line: Check only two symbols when calculating symbol size") Signed-off-by: Carlos Llamas cmllamas@google.com Acked-by: Will Deacon will@kernel.org Acked-by: Brian Johannesmeyer bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- scripts/faddr2line | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/faddr2line b/scripts/faddr2line index fe0cc45f03be1..1fa6beef9f978 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -252,7 +252,7 @@ __faddr2line() { found=2 break fi - done < <(echo "${ELF_SYMS}" | sed 's/[.*]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2 | ${GREP} -A1 --no-group-separator " ${sym_name}$") + done < <(echo "${ELF_SYMS}" | sed 's/[.*]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)
if [[ $found = 0 ]]; then warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"